Ann D. Montgomery (born 1949) is a United States federal judge.
Born in Litchfield, Minnesota, Montgomery received a B.S. from the University of Kansas in 1971 and a J.D. from the University of Minnesota Law School in 1974. She was a law clerk to Gerard Reilly and Hubert Pair, both of the U.S. Court of Appeals, District of Columbia Circuit from 1974 to 1975. She was an assistant United States Attorney of the District of Minnesota from 1976 to 1983. She was a judge on the Hennepin County Municipal Court, Minnesota from 1983 to 1985, and of the county's District Court in Minneapolis, Minnesota from 1985 to 1994.
Montgomery became a United States Magistrate Judge for the United States District Court for the District of Minnesota in 1994. On November 27, 1995, Montgomery was nominated by President Bill Clinton to a seat on the United States District Court for the District of Minnesota vacated by Diana E. Murphy. Montgomery was confirmed by the United States Senate on August 2, 1996, and received her commission on August 6, 1996.