Dennis R. Frederickson (born July 27, 1939) is a Republican politician from Minnesota and a former Minnesota State Senator. He was first elected in 1980 when he ran for the seat being vacated by Senator Carl Jensen, who was appointed to the Minnesota Tax Court and did not seek re-election. He was re-elected in 1982, 1986, 1990, 1992, 1996, 2000, 2002 and 2006, receiving only one serious challenge for the position back in 1982 from former New Ulm mayor and state representative Tony Eckstein.