JUNO THERAPEUTICS, INC. 2014 EQUITY INCENTIVE PLAN RESTRICTED STOCK UNIT AWARD AGREEMENT NOTICE OF GRANT OF RESTRICTED STOCK UNITS

EXHIBIT 10.3

JUNO THERAPEUTICS, INC.

2014 EQUITY INCENTIVE PLAN

RESTRICTED STOCK UNIT AWARD AGREEMENT

NOTICE OF GRANT OF RESTRICTED STOCK UNITS

Unless otherwise defined herein, the terms defined in the 2014 Equity Incentive Plan (the “Plan”) shall have the same defined meanings in this Restricted Stock Unit Award Agreement, including the Notice of Grant of Restricted Stock Units (the “Notice of Grant”), the Terms and Conditions of Restricted Stock Unit Grant, and any appendices and exhibits attached thereto (all together, the “Award Agreement”).

The undersigned Participant has been granted the right to receive an Award of Restricted Stock Units, subject to the terms and conditions of the Plan and this Award Agreement, as follows:

Vesting Schedule:

Subject to any acceleration provisions contained in the Plan or set forth below, the Restricted Stock Units will vest in accordance with the following schedule:

100% of the Restricted Stock Units will be fully vested on the Date of Grant.

Settlement Date:

[Shares shall be issued on the earliest to occur of: (1) [DATE]; (2) Participant’s separation from service (within the meaning of Code Section 409A); (3) a Change in Control; or (4) Participant’s death (as applicable, the “Settlement Date”). In all instances, subject to the terms of this Award Agreement, the Shares will be issued within sixty (60) days of the applicable Settlement Date and if the sixty (60) day period straddles two calendar years, Participant will not under any circumstances be permitted, directly or indirectly, to designate the taxable year in which the Restricted Stock Units are settled.]¹

[Shares shall be issued on the earliest to occur of: (1) Participant’s separation from service (within the meaning of Code Section 409A); (2) a Change in Control; or (3) Participant’s death (as applicable, the “Settlement Date”). In all instances, subject to the terms of this Award Agreement, the Shares will be issued within sixty (60) days of the applicable Settlement Date and if the sixty (60) day period straddles two calendar years, Participant will not under any circumstances be permitted, directly or indirectly, to designate the taxable year in which the Restricted Stock Units are settled.]²

Participant acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and provisions thereof, and hereby accepts this Award Agreement subject to all of the terms and provisions thereof. Participant has reviewed the Plan and this Award Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Award Agreement and fully understands all provisions of this Award Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan, this Award Agreement, or Participant’s Restricted Stock Unit Election Form dated [                ]. Participant further agrees to notify the Company upon any change in the residence address indicated below.

JUNO THERAPEUTICS, INC.

2014 EQUITY INCENTIVE PLAN

RESTRICTED STOCK UNIT AWARD AGREEMENT

TERMS AND CONDITIONS OF RESTRICTED STOCK UNIT GRANT

1. Grant of Restricted Stock Units. The Company hereby grants to the individual (the “Participant”) named in the Notice of Grant of Restricted Stock Units of this Award Agreement (the “Notice of Grant”) under the Plan an Award of Restricted Stock Units, subject to all of the terms and conditions in this Award Agreement and the Plan, which is incorporated herein by reference. Subject to Section 19(c) of the Plan, in the event of a conflict between the terms and conditions of the Plan and this Award Agreement, the terms and conditions of the Plan shall prevail.

2. Company’s Obligation to Pay.

(a) General Rule. Each Restricted Stock Unit represents the right to receive a Share on the Settlement Date (to the extent vested). Prior to the Settlement Date, such Restricted Stock Unit will represent an unsecured obligation of the Company, payable (if at all) only from the general assets of the Company. Subject to Section 2(b), any Restricted Stock Units will be paid to Participant (or in the event of Participant’s death, to his or her properly designated beneficiary or estate) in whole Shares as soon as practicable after the Settlement Date, but in each such case within sixty (60) days following the Settlement Date. If the sixty (60) day period straddles two calendar years, Participant will not under any circumstances be permitted, directly or indirectly, to designate the taxable year in which the Restricted Stock Units are settled.

(b) Section 409A. Notwithstanding anything in the Plan or this Award Agreement to the contrary, if the Settlement Date is Participant’s “separation from service” within the meaning of Section 409A, as determined by the Company, other than due to Participant’s death, and if (x) Participant is a “specified employee” within the meaning of Section 409A on that date, and (y) the payment of such accelerated Restricted Stock Units will result in the imposition of additional tax under Section 409A if paid to Participant on or within the six (6) month period following Participant’s separation from service, then the payment of the Restricted Stock Units will not be made until the date six (6) months and one (1) day following the date of Participant’s separation from service, unless Participant dies following his or her separation from service, in which case, the Restricted Stock Units will be paid in Shares to Participant’s estate as soon as practicable following his or her death. It is the intent of this Award Agreement to comply with the requirements of Section 409A so that none of the Restricted Stock Units provided under this Agreement or Shares issuable thereunder will be subject to the additional tax imposed under Section 409A, and any ambiguities herein will be interpreted to so comply. Each payment payable under this Award Agreement is intended to constitute a separate payment for purposes of Treasury Regulation Section 1.409A-2(b)(2). For purposes of this Agreement, “Section 409A” means Code Section 409A and any proposed, temporary or final Treasury Regulations and Internal Revenue Service guidance thereunder, as each may be amended from time to time.

3. Death of Participant. Any distribution or delivery to be made to Participant under this Award Agreement will, if Participant is then deceased, be made to Participant’s designated

beneficiary, or if no beneficiary survives Participant, the administrator or executor of Participant’s estate. Any such transferee must furnish the Company with (a) written notice of his or her status as transferee, and (b) evidence satisfactory to the Company to establish the validity of the transfer and compliance with any laws or regulations pertaining to said transfer.

4. Tax Consequences. Participant has reviewed with its own tax advisors the U.S. federal, state, local and foreign tax consequences of this investment and the transactions contemplated by this Award Agreement. With respect to such matters, Participant relies solely on such advisors and not on any statements or representations of the Company or any of its agents, written or oral. Participant understands that Participant (and not the Company) shall be responsible for Participant’s own tax liability that may arise as a result of this investment or the transactions contemplated by this Award Agreement.

5. Tax Obligations. Participant acknowledges that, regardless of any action taken by the Company, the ultimate liability for any tax and/or social insurance liability obligations and requirements in connection with the Restricted Stock Units, including, without limitation, (a) all federal, state, and local taxes (including the Participant’s Federal Insurance Contributions Act (FICA) obligation) that are required to be withheld by the Company or other payment of tax-related items related to Participant’s participation in the Plan and legally applicable to Participant, (b) the Participant’s and, to the extent required by the Company, the Company’s fringe benefit tax liability, if any, associated with the grant, vesting, or settlement of the Restricted Stock Units or sale of Shares, and (c) any other Company taxes the responsibility for which the Participant has, or has agreed to bear, with respect to the Restricted Stock Units (or settlement thereof or issuance of Shares thereunder) (collectively, the “Tax Obligations”), is and remains Participant’s responsibility and may exceed the amount actually withheld by the Company. Participant further acknowledges that the Company (i) make no representations or undertakings regarding the treatment of any Tax Obligations in connection with any aspect of the Restricted Stock Units, including, but not limited to, the grant, vesting or settlement of the Restricted Stock Units, the subsequent sale of Shares acquired pursuant to such settlement and the receipt of any dividends or other distributions, and (ii) do not commit to and are under no obligation to structure the terms of the grant or any aspect of the Restricted Stock Units to reduce or eliminate Participant’s liability for Tax Obligations or achieve any particular tax result. Further, if Participant is subject to Tax Obligations in more than one jurisdiction between the Date of Grant and the date of any relevant taxable or tax withholding event, as applicable, Participant acknowledges that the Company may be required to withhold or account for Tax Obligations in more than one jurisdiction. If Participant fails to make satisfactory arrangements for the payment of any required Tax Obligations hereunder at the time of the applicable taxable event, Participant acknowledges and agrees that the Company may refuse to issue or deliver the Shares. When Shares are issued as payment for vested Restricted Stock Units, Participant generally will recognize immediate U.S. taxable income if Participant is a U.S. taxpayer. If Participant is a non-U.S. taxpayer, Participant will be subject to applicable taxes in his or her jurisdiction.

6. Rights as Stockholder. Neither Participant nor any person claiming under or through Participant will have any of the rights or privileges of a stockholder of the Company in respect of any Shares deliverable hereunder unless and until certificates representing such Shares (which may be in book entry form) will have been issued, recorded on the records of the Company or its transfer

agents or registrars, and delivered to Participant (including through electronic delivery to a brokerage account). After such issuance, recordation and delivery, Participant will have all the rights of a stockholder of the Company with respect to voting such Shares and receipt of dividends and distributions on such Shares.

7. No Guarantee of Continued Service. PARTICIPANT ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER DO NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A SERVICE PROVIDER FOR ANY PERIOD, OR AT ALL, AND SHALL NOT INTERFERE IN ANY WAY WITH PARTICIPANT’S RIGHT OR THE RIGHT OF THE COMPANY TO TERMINATE PARTICIPANT’S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT CAUSE.

8. Grant is Not Transferable. Except to the limited extent provided in Section 3, this grant and the rights and privileges conferred hereby will not be transferred, assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and will not be subject to sale under execution, attachment or similar process. Upon any attempt to transfer, assign, pledge, hypothecate or otherwise dispose of this grant, or any right or privilege conferred hereby, or upon any attempted sale under any execution, attachment or similar process, this grant and the rights and privileges conferred hereby immediately will become null and void.

9. Nature of Grant. In accepting the grant, Participant acknowledges, understands and agrees that:

(a) the grant of the Restricted Stock Units is voluntary and occasional and does not create any contractual or other right to receive future grants of Restricted Stock Units, or benefits in lieu of Restricted Stock Units, even if Restricted Stock Units have been granted in the past;

(b) all decisions with respect to future Restricted Stock Units or other grants, if any, will be at the sole discretion of the Company;

(c) Participant is voluntarily participating in the Plan;

(d) the Restricted Stock Units and the Shares subject to the Restricted Stock Units are not intended to replace any pension rights or compensation;

(e) the Restricted Stock Units and the Shares subject to the Restricted Stock Units, and the income and value of same, are not part of normal or expected compensation for purposes of calculating any severance, resignation, termination, redundancy, dismissal, end-of-service payments, bonuses, long-service awards, pension or retirement or welfare benefits or similar payments;

(f) the future value of the underlying Shares is unknown, indeterminable and cannot be predicted;

(g) for purposes of the Restricted Stock Units, Participant’s status as a Service Provider will be considered terminated as of the date Participant is no longer actively providing services to the Company or any Parent or Subsidiary (regardless of the reason for such termination

and whether or not later to be found invalid or in breach of employment laws in the jurisdiction where Participant is a Service Provider or the terms of Participant’s employment or service agreement, if any), and unless otherwise expressly provided in this Award Agreement (including by reference in the Notice of Grant to other arrangements or contracts) or determined by the Administrator, Participant’s right to vest in the Restricted Stock Units under the Plan, if any, will terminate as of such date and will not be extended by any notice period (e.g., Participant’s period of service would not include any contractual notice period or any period of “garden leave” or similar period mandated under employment laws in the jurisdiction where Participant is a Service Provider or the terms of Participant’s employment or service agreement, if any, unless Participant is providing bona fide services during such time); the Administrator shall have the exclusive discretion to determine when Participant is no longer actively providing services for purposes of the Restricted Stock Units grant (including whether Participant may still be considered to be providing services while on a leave of absence);

(h) unless otherwise provided in the Plan or by the Company in its discretion, the Restricted Stock Units and the benefits evidenced by this Award Agreement do not create any entitlement to have the Restricted Stock Units or any such benefits transferred to, or assumed by, another company nor be exchanged, cashed out or substituted for, in connection with any corporate transaction affecting the Shares; and

(i) the following provisions apply only if Participant is providing services outside the United States:

10. No Advice Regarding Grant. The Company is not providing any tax, legal or financial advice, nor is the Company making any recommendations regarding Participant’s participation in the Plan, or Participant’s acquisition or sale of the underlying Shares. Participant is hereby advised to consult with his or her own personal tax, legal and financial advisors regarding his or her participation in the Plan before taking any action related to the Plan.

11. Data Privacy. Participant hereby explicitly and unambiguously consents to the collection, use and transfer, in electronic or other form, of Participant’s personal data as described in this Award Agreement and any other Restricted Stock Unit grant materials by and among, as applicable, the Company and any Parent or Subsidiary for the exclusive purpose of implementing, administering and managing Participant’s participation in the Plan.

Participant understands that the Company may hold certain personal information about Participant, including, but not limited to, Participant’s name, home address and telephone number, date of birth, social insurance number or other identification number, salary, nationality, job title, any Shares or directorships held in the Company, details of all Restricted Stock Units or any other entitlement to Shares awarded, canceled, exercised, vested, unvested or outstanding in Participant’s favor (“Data”), for the exclusive purpose of implementing, administering and managing the Plan.

Participant understands that Data will be transferred to a stock plan service provider as may be selected by the Company in the future, which is assisting the Company with the implementation, administration and management of the Plan. Participant understands that the recipients of the Data may be located in the United States or elsewhere, and that the recipients’ country of operation (e.g., the United States) may have different data privacy laws and protections than Participant’s country. Participant understands that if he or she resides outside the United States, he or she may request a list with the names and addresses of any potential recipients of the Data by contacting his or her local human resources representative. Participant authorizes the Company, any stock plan service provider selected by the Company and any other possible recipients which may assist the Company (presently or in the future) with implementing, administering and managing the Plan to receive, possess, use, retain and transfer the Data, in electronic or other form, for the sole purpose of implementing, administering and managing his or her participation in the Plan. Participant understands that Data will be held only as long as is necessary to implement, administer and manage Participant’s participation in the Plan. Participant understands if he or she resides outside the United States, he or she may, at any time, view Data, request additional information about the storage and processing of Data, require any necessary amendments to Data or refuse or withdraw the consents herein, in any case without cost, by contacting in writing his or her local human resources representative. Further, Participant understands that he or she is providing the consents herein on a purely voluntary basis. If Participant does not consent, or if Participant later seeks to revoke his or her consent, his or her status as a Service Provider will not be adversely affected; the only adverse

consequence of refusing or withdrawing Participant’s consent is that the Company would not be able to grant Participant Restricted Stock Units or other equity awards or administer or maintain such awards. Therefore, Participant understands that refusing or withdrawing his or her consent may affect Participant’s ability to participate in the Plan. For more information on the consequences of Participant’s refusal to consent or withdrawal of consent, Participant understands that he or she may contact his or her local human resources representative.

12. Address for Notices. Any notice to be given to the Company under the terms of this Award Agreement will be addressed to the Company at Juno Therapeutics, Inc., 307 Westlake Avenue North, Suite 300, Seattle, WA 98109, or at such other address as the Company may hereafter designate in writing.

13. Electronic Delivery and Acceptance. The Company may, in its sole discretion, decide to deliver any documents related to the Restricted Stock Units awarded under the Plan or future Restricted Stock Units that may be awarded under the Plan by electronic means or request Participant’s consent to participate in the Plan by electronic means. Participant hereby consents to receive such documents by electronic delivery and agrees to participate in the Plan through any on-line or electronic system established and maintained by the Company or another third party designated by the Company.

14. No Waiver. Either party’s failure to enforce any provision or provisions of this Agreement shall not in any way be construed as a waiver of any such provision or provisions, nor prevent that party from thereafter enforcing each and every other provision of this Agreement. The rights granted both parties herein are cumulative and shall not constitute a waiver of either party’s right to assert all other legal remedies available to it under the circumstances.

15. Successors and Assigns. The Company may assign any of its rights under this Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon Participant and his or her heirs, executors, administrators, successors and assigns. The rights and obligations of Participant under this Agreement may only be assigned with the prior written consent of the Company.

16. Additional Conditions to Issuance of Stock. If at any time the Company will determine, in its discretion, that the listing, registration, qualification or rule compliance of the Shares upon any securities exchange or under any state, federal or foreign law, the tax code and related regulations or under the rulings or regulations of the United States Securities and Exchange Commission or any other governmental regulatory body or the clearance, consent or approval of the United States Securities and Exchange Commission or any other governmental regulatory authority is necessary or desirable as a condition to the issuance of Shares to Participant (or his or her estate) hereunder, such issuance will not occur unless and until such listing, registration, qualification, rule compliance, clearance, consent or approval will have been completed, effected or obtained free of any conditions not acceptable to the Company. Subject to the terms of the Agreement and the Plan, the Company shall not be required to issue any certificate or certificates for Shares hereunder prior to the lapse of such reasonable period of time following the date of vesting of the Restricted Stock Units as the Administrator may establish from time to time for reasons of administrative convenience.

17. Language. If Participant has received this Agreement or any other document related to the Plan translated into a language other than English and if the meaning of the translated version is different than the English version, the English version will control.

18. Interpretation. The Administrator will have the power to interpret the Plan and this Award Agreement and to adopt such rules for the administration, interpretation and application of the Plan as are consistent therewith and to interpret or revoke any such rules (including, but not limited to, the determination of whether or not any Restricted Stock Units have vested). All actions taken and all interpretations and determinations made by the Administrator in good faith will be final and binding upon Participant, the Company and all other interested persons. Neither the Administrator nor any person acting on behalf of the Administrator will be personally liable for any action, determination or interpretation made in good faith with respect to the Plan or this Award Agreement.

19. Captions. Captions provided herein are for convenience only and are not to serve as a basis for interpretation or construction of this Award Agreement.

20. Modifications to the Agreement. This Award Agreement constitutes the entire understanding of the parties on the subjects covered. Participant expressly warrants that he or she is not accepting this Award Agreement in reliance on any promises, representations, or inducements other than those contained herein. Modifications to this Award Agreement or the Plan can be made only in an express written contract executed by a duly authorized officer of the Company. Notwithstanding anything to the contrary in the Plan or this Award Agreement, the Company reserves the right to revise this Award Agreement as it deems necessary or advisable, in its sole discretion and without the consent of Participant, to comply with Section 409A or to otherwise avoid imposition of any additional tax or income recognition under Section 409A in connection to this Award of Restricted Stock Units.

21. Governing Law and Venue. This Award Agreement will be governed by the laws of Washington, without giving effect to the conflict of law principles thereof. For purposes of litigating any dispute that arises under the Restricted Stock Units or this Award Agreement, the parties hereby submit to and consent to the jurisdiction of the State of Washington, and agree that such litigation will be conducted in the courts of Seattle, Washington or the federal courts for the United States for the District of Washington, and no other courts.

22. Agreement Severable. In the event that any provision in this Award Agreement will be held invalid or unenforceable, such provision will be severable from, and such invalidity or unenforceability will not be construed to have any effect on, the remaining provisions of this Award Agreement.

23. Amendment, Suspension or Termination of the Plan. By accepting this Award, Participant expressly warrants that he or she has received Restricted Stock Units under the Plan, and has received, read and understood a description of the Plan. Participant understands that the Plan is discretionary in nature and may be amended, suspended or terminated by the Company at any time.

24. Entire Agreement. The Plan is incorporated herein by reference. The Plan, this Award Agreement (including the exhibits referenced herein) and Participant’s Restricted Stock Unit

Election Form dated [                ] constitute the entire agreement of the parties with respect to the subject matter hereof and supersede in their entirety all prior undertakings and agreements of the Company and Participant with respect to the subject matter hereof, and may not be modified adversely to the Participant’s interest except by means of a writing signed by the Company and Participant.

25. [Country Addendum. Notwithstanding any provisions in this Award Agreement, the Restricted Stock Unit grant shall be subject to any special terms and conditions set forth in any appendix to this Award Agreement for Participant’s country. Moreover, if Participant relocates to one of the countries included in the Country Addendum, the special terms and conditions for such country will apply to Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons. The Country Addendum constitutes part of this Award Agreement.]

JUNO THERAPEUTICS, INC.

2014 EQUITY INCENTIVE PLAN

RESTRICTED STOCK UNIT AGREEMENT

COUNTRY ADDENDUM

TERMS AND CONDITIONS

This Country Addendum includes additional terms and conditions that govern the award of Restricted Stock Units under the Plan if Participant works in one of the countries listed below. If Participant is a citizen or resident of a country (or is considered as such for local law purposes) other than the one in which he or she is currently working or if Participant relocates to another country after receiving the Award of Restricted Stock Units, the Company will, in its discretion, determine the extent to which the terms and conditions contained herein will be applicable to Participant.

Certain capitalized terms used but not defined in this Country Addendum shall have the meanings set forth in the Plan and/or the Award Agreement to which this Country Addendum is attached.

NOTIFICATIONS

This Country Addendum also includes notifications relating to exchange control and other issues of which Participant should be aware with respect to his or her participation in the Plan. The information is based on the exchange control, securities and other laws in effect in the countries listed in this Country Addendum, as of [DATE]. Such laws are often complex and change frequently. As a result, the Company strongly recommends that Participant not rely on the notifications herein as the only source of information relating to the consequences of his or her participation in the Plan because the information may be outdated when Participant vests in the Restricted Stock Units and acquires Shares, or when Participant subsequently sell Shares acquired under the Plan.

In addition, the notifications are general in nature and may not apply to Participant’s particular situation, and the Company is not in a position to assure Participant of any particular result. Accordingly, Participant is advised to seek appropriate professional advice as to how the relevant laws in Participant’s country may apply to Participant’s situation.

Finally, if Participant is a citizen or resident of a country other than the one in which Participant is currently working (or is considered as such for local law purposes) or if Participant moves to another country after receiving an Award of Restricted Stock Units, the information contained herein may not be applicable to Participant.