The 2016 Ohio Democratic presidential primary took place on March 15 in the U.S. state of Ohio as one of the Democratic Party's primaries prior to the 2016 presidential election.

Presidential primaries and caucuses were organized by the Democratic Party to select the 4,051 delegates to the 2016 Democratic National Convention held July 25–28 and determine the nominee for president in the 2016 United States presidential election. The elections took place within all fifty U.S. states, the District of Columbia, five U.S. territories, and Democrats Abroad and occurred between February 1 and June 14, 2016.