Starboard Value SC 13D AECOM / Starboard Value ownership change

Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including additional amendments thereto) with respect to the shares of Common Stock, $0.01 par value, of AECOM. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated: November 30, 2020

STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD By: Starboard Value LP, its investment manager   Starboard Value and Opportunity S LLC By: Starboard Value LP, its manager   Starboard Value and Opportunity C LP By: Starboard Value R LP, its general partner   STARBOARD VALUE AND OPPORTUNITY MASTER FUND L LP By: Starboard Value L LP, its general partner   Starboard Value L LP By: Starboard Value R GP LLC, its general partner   STARBOARD VALUE R LP By: Starboard Value R GP LLC, its general partner   STARBOARD P FUND LP By: Starboard Value P GP LLC, its general partner   STARBOARD VALUE P GP LLC By: Starboard Value R LP, its member   STARBOARD LEADERS YANKEE LLC By: Starboard Value A LP, its managing member Starboard Leaders Fund LP By: Starboard Value A LP, its general partner   Starboard Leaders Select X LP By: Starboard Leaders Select X GP LLC, its general partner   STARBOARD VALUE A LP By: Starboard Value A GP LLC, its general partner   STARBOARD VALUE X MASTER FUND LTD By: Starboard Value LP, its investment manager   STARBOARD VALUE LP By: Starboard Value GP LLC, its general partner   STARBOARD VALUE GP LLC By: Starboard Principal Co LP, its member   STARBOARD PRINCIPAL CO LP By: Starboard Principal Co GP LLC, its general partner   STARBOARD PRINCIPAL CO GP LLC   Starboard Value A GP LLC   Starboard Value R GP LLC   Starboard Leaders Select X GP LLC

By:	/s/ Jeffrey C. Smith
	Name:	Jeffrey C. Smith
	Title:	Authorized Signatory

/s/ Jeffrey C. Smith

Jeffrey C. Smith

Individually and as attorney-in-fact for Peter A. Feld