Robert Landis Armstrong, known as Bob Armstrong, was a Democratic politician and an environmental activist from the U.S. state of Texas. He was a member of the Texas House of Representatives from 1963 to 1971, Commissioner of the Texas General Land Office from 1971 to 1983, and a member of the Texas Parks and Wildlife Commission from 1985 to 1991. From 1993 to 1998, he was the assistant secretary for land and minerals management at the United States Department of the Interior under appointment of U.S. President Bill Clinton.

The Texas General Land Office (GLO) is a state agency of the U.S. state of Texas, responsible for managing lands and mineral rights properties that are owned by the state. The GLO also manages and contributes to the state's Permanent School Fund. The agency is headquartered in the Stephen F. Austin State Office Building in Downtown Austin.