|Chairman||Nancy Patton Mills|
|Lieutenant Governor||Mike Stack|
|National affiliation||Democratic Party|
|Seats in the US Senate|
1 / 2
|Seats in the US House|
6 / 18
|Seats in the State Senate|
16 / 50
|Seats in the State House|
81 / 203
|Justices on the Supreme Court|
5 / 7
The Pennsylvania Democratic Party is the affiliate of the Democratic Party in the state of Pennsylvania. The party has had strong support in the Pittsburgh and Philadelphia area for a long time, having controlled the mayoral office in Philadelphia since 1952, and the Pittsburgh Mayoral office since 1933. As of January 20, 2015 the party holds all five statewide executive offices after electing Tom Wolf governor in the 2014 elections. This trend has continued following the 2016 Elections where all statewide Democrats were either re-elected or were replaced by another Democrat.
The state Democratic Party has recently made economic factors a major component of its platform, with advocacy for middle class workers of particular prominence. The party has also opposed Republican-sponsored legislation to require a photo ID for voting, asserting that such a requirement would discourage minorities, youth, and those with low-income from voting because they are less likely to possess a state-issued ID. Additionally, the party has committed itself to maintaining the social safety net, and encouraging more transparency in state government. 
The Pennsylvania Democratic Party traces its history to 1792. Pennsylvania Democrat James Buchanan, was elected President in 1856, but did not seek re-election four years later, when Abraham Lincoln, a Republican, was elected President. Buchanan's rise and fall from political prominence coincided with that of the state Democratic Party in Pennsylvania; for much of the late nineteenth and early twentieth century, the party was largely out of power.  
The party held the governorship from 2003 to 2011 with the election of Ed Rendell in 2002 and his re-election in 2006. The party lost control of the governorship following the election of Republican state Attorney General Tom Corbett in 2010. In the 2014 U.S elections governor Tom Corbett lost reelection to democrat Tom Wolf, the former Secretary of Revenue of Pennsylvania. The party picked up a Senate seat in 2006 with the election of Bob Casey, Jr. Pennsylvania Democrats also briefly held both of the state's U.S. Senate seats following Arlen Specter's party-switch. However, Congressman Joe Sestak defeated Specter in the May 2010 primary, before losing the fall general election to former Congressman Pat Toomey. On the state legislative level, the party won a majority in the State House in 2006 and again in 2008. The party lost its majority in that chamber in the 2010 election. The State Senate has been controlled by the Republicans for more than a decade, with the balance of power in that chamber presently standing at 30 Republicans, and 20 Democrats. 
Democrats made significant gains in voter registration during the 2008 Presidential election, with registered Democrats now outnumbering registered Republicans almost by a 3-2 margin.  Democrats now outnumber Republicans in the state of Pennsylvania by 1.2 million voters.
Incumbent Republican Governor Tom Corbett was defeated for re-election to a second term by Democrat Tom Wolf. This marked the first time an incumbent Governor running for re-election in Pennsylvania lost. 
In 2017, the Pennsylvania Democratic Party and its chair at the time, Marcel Groen, came under increasing fire for inaction in the face of calls to address what female party leaders and local activists have characterized as a culture of sexual predation within the party. Critics cited Groen's silence on sexual misconduct allegations against prominent state politicians, his failure to fulfill a commitment to create a party sexual misconduct policy after the alleged sexual assault of a state party delegate at the 2016 DNC, and his anger over calls to dismiss a close aide's controversial statements about the #MeToo movement as evidence of Groen's unwillingness to address sexual misconduct within the party.  Groen stepped down as party chair in February 2018. 
The Pennsylvania Democratic Party holds three of the state's five statewide offices and is a minority in both the Pennsylvania State Senate and Pennsylvania House of Representatives. Democrats hold one of the state's U.S. Senate seats and 6 of the state's 18 U.S. House seats.
- Governor: Tom Wolf
- Lieutenant Governor: Mike Stack
- Attorney: Josh Shapiro
- Auditor General: Eugene DePasquale
- Treasurer: Joe Torsella
- U.S. Senate
- U.S. House of Representatives
- Chair, Nancy Patton Mills
- Elections in Pennsylvania
- Green Party of Pennsylvania
- Libertarian Party of Pennsylvania
- Political party strength in Pennsylvania
- Politics of Pennsylvania
- Republican State Committee of Pennsylvania
- "NBC News Projects: PA's Corbett Ousted by Democrat Tom Wolf". NBC News. November 4, 2014. Retrieved November 4, 2014.
- Will Bunch (January 30, 2018). "Silence makers: Why did Pa. Democratic Party go MIA on sex harassment?". Philadelphia Daily News. Retrieved January 30, 2018.
- John L. Micek (February 2, 2018). "Pa. Democratic Party chairman resigns after defending lawmaker accused of sexual harassment". PennLive. Retrieved August 29, 2018.