The John N. Bagley House, also known as the Bagley Mansion, is a Romanesque Revival mansion with French Renaissance Revival influences located at 2921 East Jefferson Avenue in Detroit. Designed by Rogers and MacFarlane and completed in 1889 for John N. Bagley, son of former Michigan Governor John J. Bagley, the house is noted for its red sandstone exterior and sculptural stonework by Julius Melchers.

It was listed on the National Register of Historic Places in 1985 as part of the East Jefferson Avenue Residential Thematic Resource. Today, the building is owned and operated by Keasha Rigsby and Vallery Hyduk as a multi-tenant commercial property while retaining much of its historic character.