Exhibit 21.1

SUBSIDIARIES OF ABM INDUSTRIES INCORPORATED

The following is a list of subsidiaries of the company as of October 31, 2020, 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
			ABM International Limited			Bermuda
			ABM International (Holdings) Ltd			England
			ABM Aviation UK Limited			England
			Air Serv Middle East Hospitality Services LLC			UAE
			OFJ Connections			England
			OFJ Airlinks Limited			England
			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
			ABM International (Holdings) B.V.			Holland
			ABM Onsite Services - Canada ULC			Canada
			Westway Services Holdings (2014) Ltd.			England
			Westway Services Holdings (2010) Ltd.			England
			ABM Technical Solutions Limited			England
			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
			Linc International, Inc.			Delaware
			Linc Facility Services Iraq LLC			Delaware
			Wassl Al-Iraq Project Services & General Contracting LLPC			Iraq
			Linc Facility Services ME, LLC			Delaware
			Linc Facility Services Saudi Arabia, LLC			Saudi Arabia

*Subsidiary relationship to Company or to subsidiary parents shown by progressive indentation.