The 2008 Pennsylvania Republican presidential primary was an election held on April 22 by the Pennsylvania Department of State in which voters chose their preference for the Republican Party's candidate for the 2008 United States presidential election.

Voters also chose the Pennsylvania Republican Party's candidates for various state and local offices.

Unlike on the Democratic side, little campaigning took place as John McCain had already clinched the nomination.

Outsider candidate Ron Paul made several stops in the state, including his birthplace of Pittsburgh.

Some media sources noted that Ron Paul and Mike Huckabee combined took in around 220,000 votes (about 27% of the vote total), despite McCain's status as presumptive nominee and the statistical irrelevance of Pennsylvania, as a possible sign of continuing social conservative or libertarian unease with McCain's nomination and have speculated about whether these results could potentially affect McCain in the November general election.