Margarethe "Grethe" Cammermeyer (born March 24, 1942) is a Norwegian-American former military officer.

She served as a colonel in the Washington National Guard and became a gay rights activist.

In 1989, responding to a question during a routine security clearance interview, she disclosed that she is a lesbian.

After retirement, Cammermeyer ran for the United States Congress in Washington's 2nd congressional district in 1998.

She won the Democratic primary, but lost in the general election to Republican incumbent Jack Metcalf.