Exhibit 21.1

SUBSIDIARIES OF ABM INDUSTRIES INCORPORATED

The following is a list of subsidiaries of the company as of October 31, 2019, omitting subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary.

Company		Where Incorporated or Organized
ABM INDUSTRIES INCORPORATED		Delaware
(*)	ABM Aviation, Inc.	Georgia
	Omni Serv Limited	England
	Air Serv Middle East Hospitality Services LLC	UAE
	OFJ Connections	England
	OFJ Airlinks Limited	England
	ABM International (Holdings) B.V.	Holland
	ABM International Limited	Bermuda
	ABM Group UK Limited	England
	ABM Facility Services UK Limited	England
	ABM Facility Services Scotland Limited	England
	Eclipse Contract Cleaning Limited	Scotland
	GBM Services (Civic) Limited	England
	BRBIBR Limited	England
	ABM Critical Solutions Limited	England
	Westway Services Holdings (2014) Ltd.	England
	Westway Services Holdings (2010) Ltd.	England
	ABM Technical Solutions Limited	England
	ABM Onsite Services - Canada ULC	Canada
	ABM Building & Energy Solutions, LLC	Delaware
	ABM Building Services, LLC	Delaware
	ABM Building Solutions, LLC	Delaware
	ABM Electrical & Lighting Services, LLC	Delaware
	ABM Electrical & Lighting Solutions, Inc.	Delaware
	ABM Electrical Power Services, LLC	Delaware
	ABM Electrical Power Solutions, LLC	Delaware
	ABM Facility Support Services, LLC	Delaware
	RenewEnergy Solutions, LLC	Delaware
	ABM Franchising Group, LLC	Delaware
	ABM General Services, Inc.	Delaware
	ABM Healthcare Support Services, Inc.	Michigan
	ABM Industrial Services, Inc.	Delaware
	ABM Industry Groups, LLC	Delaware
	ABM Security Services, Inc.	California
	ABM Texas General Services, Inc.	Delaware
	Grade Sub Two, LLC	Delaware
	GCA Services Group, Inc.	Delaware
	Associated Facility Management, LLC	Nevada
	GCA Cleaning Specialties, LP	Texas
	GCA Services Group Mountain States, LP	Texas

GCA Services Group of Texas, LP	Texas
Associated Facility Ventures, LLC	Nevada
GCA Education Services, Inc.	Tennessee
GCA Education Services Central States, Inc.	Illinois
GCA Education Services of New England, Inc.	Delaware
GCA K12 Education Services, Inc.	Texas
GCA Nuclear Facility Services, Inc.	Texas
GCA Production Services, Inc.	Delaware
GCA Services Group of California, Inc.	California
GCA Services Group of Colorado, Inc.	Colorado
GCA Services Group of North Carolina, Inc.	North Carolina
GCA Services Group of Northwestern States, Inc.	Washington
GCA Staffing Services, Inc.	Delaware
National Building Maintenance Corp.	Delaware
IFM Assurance Company	New York

*Subsidiaryrelationship to Company or to subsidiary parents shown by progressive indentation.