Donna J. Seidel (born August 6, 1950) is an American former politician, police officer and investigator from Neenah, Wisconsin who served as a Democratic Party member of the Wisconsin State Assembly, representing the 85th Assembly District (Wausau and other parts of Marathon County and two tiny portions of Shawano County) from her election in 2004 until 2013.

She graduated from Neenah High School, and received a Bachelor of Science degree from the University of Wisconsin-Stevens Point in 1972.

She ran for the Assembly in 2004, was unopposed in the Democratic primary, and won the general election with 15,666 votes (57.29%) to 11,667 (42.67%) for Republican Sarah Kamke.

She was assigned to the standing committees on children and families; on corrections and the courts; on tourism; and on workforce development.

She was re-elected in 2010 with 52.53% of the vote to 43.15% for Republican Charles Eno and 4.23 percent for Libertarian Jim Maas; and remained Assistant Leader of the Assembly Democrats until she retired in 2012.