Mary Adelaide Lundby (February 2, 1948 – January 17, 2009) was a state Senator from the Iowa's 18th District. She served in the Iowa Senate from 1995 to 2009, serving as Minority Leader from 2006 to 2007 and as Co-Majority Leader in 2006. She also served in the Iowa House of Representatives from 1987 to 1995, serving as Speaker pro Tempore from 1992 to 1994. Prior to her election to the Iowa House, Lundby had served as the co-chair of the Linn County Republican party, as a member of the Linn County Republican Central Committee, and as staff assistant to then-senator Roger Jepsen. She graduated from Upper Iowa University, majoring in Political Science and History.