The 1904 United States presidential election in Pennsylvania took place on November 8, 1904 as part of the 1904 United States presidential election. Voters chose 34 representatives, or electors to the Electoral College, who voted for president and vice president.

The 1904 United States presidential election was the 30th quadrennial presidential election, held on Tuesday, November 8, 1904. Incumbent Republican President Theodore Roosevelt defeated the conservative Democratic nominee, Alton B. Parker. Roosevelt's victory made him the first president who ascended to the presidency upon the death of his predecessor to win a full term in his own right. This was also the second presidential election in which both major party candidates were registered in the same home state; the others have been in 1860, 1920, 1940, 1944, and 2016.