Rein Taagepera (born 28 February 1933) is an Estonian political scientist and politician.

Born in Tartu, Estonia, Taagepera fled from occupied Estonia in 1944. Taagepera graduated from high school in Marrakech, Morocco and then studied physics in Canada and the United States. He received a Ph.D. from the University of Delaware in 1965. Working in industry until 1970, he received another M.A. in international relations in 1969 and switched to academe as a political scientist at the University of California, Irvine, where he stayed for his entire American career.

Taagepera served as President of the Association for the Advancement of Baltic Studies from 1986 until 1988. In 1991, he returned to Estonia as the founding dean of a new School of Social Sciences at the University of Tartu, which merged into a full-fledged faculty in 1994, and where he also became Professor of Political Science (1994–1998).

In 1991, he was a member of the Estonian Constitutional Assembly, and in 1992, he ran as a presidential candidate against Arnold Rüütel (3rd President of the Republic of Estonia, 2001–2006), and Lennart Meri (2nd President of the Republic of Estonia, 1992–2001), who won the election. Taagepera came in third with 23% of the popular vote. Later Taagepera admitted that one of the reasons why he ran, despite having little chance to win, was to take away votes from Rüütel and thus help Meri rise to the presidency.

Taagepera is a village in Helme Parish, Valga County, in southern Estonia. It has a population of 109 (as of 1 January 2011).

Taagepera is famous for its Jugendstil castle.