The Women’s Union of Baltimore was a feminist organization that operated in Baltimore, Maryland in the 1970s. Started in 1972, the group had strong ideological ties to both socialism and lesbianism, which over time was broadened to terms described as "radical" and “women loving women, whether a sexual relationship or not.” These core values were part of the Women's Union of Baltimore's Principles of Unity.

Primarily a reading, discussion, and study group, the Women’s Union of Baltimore was also involved with tenants’ rights, hospital protests, picketing of the Exxon fuel company, and advocacy efforts for diversity at the 1977 International Women’s Year Conference. In 1976, the organization presented a night of performances and lectures related to injustices against women in the grand jury process at an event called “Knock, Knock, Who’s There?”

Source: Women's Union of Baltimore flyer, undated