The Defense Industry is the worldwide industrial complex that enables research and development, as well as design, production, delivery, and maintenance of military weapons systems, subsystems, and components or parts, to meet U.S. military requirements.

The Defense Industrial Base partnership consists of Department of Defense components, more than 100,000 Defense Industrial Base companies and their subcontractors who perform under contract to the Department of Defense, companies providing incidental materials and services to the Department of Defense, and government-owned/contractor-operated and government-owned/ government-operated facilities.

Defense Industry companies include domestic and foreign entities, with production assets located in many countries. The sector provides products and services that are essential to mobilize, deploy, and sustain military operations. The Defense Industrial Base Sector does not include the commercial infrastructure of providers of services such as power, communications, transportation, or utilities that the Department of Defense uses to meet military operational requirements.

Publicly traded Defense Industry companies include Lockheed Martin (LMT), Northrop Grumman (NOC), and Raytheon Technologies (RTX). The Invesco Aerospace & Defense ETF (PPA) holds a broad range of stocks, including some from companies that are not pure-play defense companies.