The Dōmei Seisha (lit. Union Association) was a political party in Japan.
The party was established as the Dōmei Club (同志倶楽部) in November 1892 by a group of 24 mostly independent MPs. It gradually became closer to the Rikken Kaishintō, and in January 1894 was renamed the Dōmei Seisha after becoming a political association.
The party won 24 seats in the March 1894 elections, and in May that year it merged with Dōshi Seisha to form Rikken Kakushintō.