The 2012 United States presidential election in Pennsylvania took place on November 6, 2012, as part of the 2012 United States presidential election in which all 50 states plus the District of Columbia participated. The primary election to select the Democratic and Republican candidates had been held on April 24, 2012. Pennsylvania voters chose 20 electors to represent them in the Electoral College via a popular vote pitting incumbent Democratic President Barack Obama and his running mate, Vice President Joe Biden, against Republican challenger and former Massachusetts Governor Mitt Romney and his running mate, Congressman Paul Ryan. Pennsylvania's electoral vote number was a reduction from the 2008 delegation, which had 21 electors. This change was due to reapportionment following the 2010 United States Census. Pennsylvania's 20 electoral votes are allotted on a winner-take-all basis.

The 2004 United States presidential election in Pennsylvania took place on November 2, 2004, and was part of the 2004 United States presidential election. Voters chose 21 representatives, or electors to the Electoral College, who voted for president and vice president.