FIFTH AMENDMENT TO THE TRUST AGREEMENT UNDER THE CONOCOPHILLIPS COMPANY GRANTOR TRUSTAGREEMENT

Exhibit 10.17.8

FIFTH AMENDMENT TO THE TRUST AGREEMENT UNDER THE

CONOCOPHILLIPS COMPANY

GRANTOR TRUST AGREEMENT

WHEREAS, Phillips Petroleum Company (now ConocoPhillips Company, hereinafter “Company”) and Wachovia Bank, National Association (now Wells Fargo Bank, N.A., hereinafter the “Trustee”) entered into an amended and restated trust agreement as of June 1, 1998, subsequently amended as of May 3, 1999, as of January 15, 2002, as of October 5, 2006, and as of May 1, 2012 (the “Trust Agreement”), establishing a trust (the “Trust”) for the purpose of holding monies and other property in connection with certain nonqualified deferred compensation plans maintained by the Company (the “Plans”); and

WHEREAS, pursuant to Section 14(a) of the Trust Agreement, the Trust Agreement may be amended by a written instrument executed by the Trustee and the Company;

NOW, THEREFORE, the Trust Agreement is amended, effective May 1, 2015, as follow:

The Trust Agreement is in all other respects ratified and confirmed without amendment.

IN WITNESS WHEREOF, this amendment to the Trust Agreement has been executed on behalf of the parties hereto on the 20 day of May, 2015.