The U.S. company said the companies selected under the Australian Defense and Materiel Organization's Global Supply Chain Program are Electro Optic Systems, CEA Technologies and Insitec.
Those companies, with expertise in aerospace hardware and software, will supply a variety of products and services for Northrop programs.
"Northrop Grumman's commitment to Australia is underscored by genuine and direct investment in the Australian economy," said David Perry, vice president and chief global business development officer, Northrop Grumman.
"EOS, CEA Technologies and Insitec represent Australia's vibrant defense industry and are key additions to our Australian industry team.
"Each of these relationships strengthens our ability to deliver products and services critical to maintaining the national security of the United States, Australia and our allies.
"We look forward to further expanding our global supply chain and to future investment in Australia's defense, aerospace and space sector," he said.
Northrop Grumman and the Australian Department of Defense in 2011 agreed to cooperate to identify opportunities in which Australian industry could work with the company.