The 1812 United States Senate election in Pennsylvania was held on December 8, 1812. Abner Lacock was elected by the Pennsylvania General Assembly to the United States Senate.[1]
Incumbent Democratic-Republican Andrew Gregg, who was elected in 1806, was not a candidate for re-election to another term. The Pennsylvania General Assembly, consisting of the House of Representatives and the Senate, convened on December 8, 1812, to elect a new Senator to fill the term beginning on March 4, 1813. The results of the vote of both houses combined are as follows:
|-|-bgcolor="#EEEEEE"| colspan="3" align="right" | Totals| align="right" | 126| align="right" | 100.00%|}