Ballston–MU station is a side platformed Washington Metro station in Arlington County, Virginia. The station opened on December 1, 1979, and is operated by the Washington Metropolitan Area Transit Authority (WMATA). The station is part of the Orange and Silver Lines and serves the transit-oriented community of Ballston, Ballston Quarter, and Marymount University (MU).

The Orange Line is a rapid transit line of the Washington Metro system, consisting of 26 stations in Fairfax County and Arlington in Northern Virginia; Washington, D.C.; and Prince George's County, Maryland, United States. The Orange Line runs from Vienna in Virginia to New Carrollton in Maryland. Half of the line's stations are shared with the Blue Line and over two thirds are shared with the Silver Line. Orange Line service began on November 20, 1978.