Venus Alley was a famous red-light district once located in Butte, Montana in the United States. It flourished from the late 19th century through the early 20th century and was one the last openly tolerated urban prostitution districts in the American West, along with the one in Reno, Nevada. It was closed in the 1920s.

Venus Alley rose in the 1880s during the hey-day of Butte as a wide-open copper-mining town, full of hundreds of saloons and gambling halls. The block-long district was located in the center of town off Wyoming Street. The name "Venus Alley" came from the rear entrance of the famous Dumas Brothel, one of the longest running houses of prostitution in the U.S. The brick-lined alley was lined with "cribs", overhung with a single white light bulb over each entrance. The north side of the alley was lined with the famous "double-deckers", where the alley-level cribs were surmounted by a wooden planks and a second row of cribs. The women who worked the cribs typically wore brightly-colored and short-skirted dresses. The cribs were equipped with callboxes for ordering drinks or food from nearby bars and noodle parlors.

The structure of the Dumas Brothel, as well as the brick-lined alley, still stands in downtown Butte and has become a tourist attraction.