Gregory Robert Dahlberg (born November 23, 1951) was United States Under Secretary of the Army from 2000 to 2001.

After graduating, Dahlberg took a job with the United States Department of Transportation in the Office of the Assistant Secretary for Budget and Program, with his work focusing on highway construction and budget and finance issues related to transportation.

In 1981, he joined the staff of the United States House Appropriations Subcommittee on Transportation, Housing and Urban Development, and Related Agencies, a subcommittee of the United States House Committee on Appropriations; there, he worked on the budgets of the Federal Highway Administration, the National Highway Traffic Safety Administration, the Urban Mass Transportation Administration, Amtrak, Conrail, and the United States Coast Guard.

While on the staff of the House Appropriations Committee, he also worked on the FDA Fast Track Development Program, and the special financing structure of Operation Desert Storm.

Since leaving the United States Department of the Army in 2001, Dahlberg worked for Lockheed Martin as Senior Vice President, Strategic Enterprises, retiring in August 2015.