The Philadelphia Big 5 is an informal association of college athletic programs in Philadelphia, Pennsylvania, USA. It is not a conference; indeed the five schools that are members of the Big 5 are members of three separate conferences: the Atlantic Ten, the Big East, and the Ivy League.
The five universities that compose the Big 5 are the University of Pennsylvania, Temple University, Saint Joseph's University, Villanova University, and La Salle University. Four of the Philadelphia Big 5 schools are within (or mostly within) the city limits (the campus of Saint Joseph's University straddles the city's border). The fifth, Villanova, is located in a nearby Main Line suburb.
The Big 5 was formed in 1955 in order to showcase the rich basketball talent in the city and help pay for the upkeep on the Palestra, where the games historically took place. All schools agreed to split ticket and concessions revenues equally once Penn was paid for upkeep costs on the Palestra. The intense rivalries between the teams and the proximity of the schools and their fans make the Big 5 a unique tradition in college basketball.
Historically, games were played as double or tripleheaders. However, it has been argued that changes in the structure of college basketball in the last quarter of the 20th century caused the Big 5 to lose much of its significance. During the heyday of the Big 5, many major college programs, especially in the northeastern United States, were independents. As the Big East and Atlantic Ten Conferences expanded to cover most of the Northeast (Villanova joined the Big East, while Temple, St. Joseph's, and La Salle joined the Atlantic Ten), and as college basketball became increasingly driven by television and its need to appeal to a broad national audience, the local character of the Big 5 was a liability. The round-robin series ended in 1991.
In 1999, the Big 5 round-robin series was revived, and has continued to this day. Some things have changed from the series' heyday: the schools no longer evenly split the proceeds from the games, and La Salle, Temple, and Villanova do not always use the Palestra for their home games in the series. Nonetheless, the revival of the Big 5 provides a living link to the past of college basketball.
Each year the Herb Good Basketball Club selects All-Big 5 teams, as well as a coach of the year and the most outstanding player receives the Robert V. Geasey Trophy.
The Big 5 creed reads, "They say there is no real prize for winning the Big Five. They must not be from Philly."
There are a few intense rivalries inside the Big 5, most notably the rivalry between Villanova and Saint Joseph's, also known as the Holy War. The rivalry between Saint Joseph's and Temple has increased in intensity in recent years, mostly because of the "Goon Gate" incident in 2005 involving former Temple coach John Chaney where he sent in a player to intentionally foul an SJU player which led to John Bryant's fractured arm. La Salle considers Saint Joseph's to be its biggest rival.
As of 2008, at least one team from the Big 5 had made it into the NCAA Tournament for 31 consecutive years.
Recently there has been talk of officially including Drexel in the Big 5. These talks amplified in the 2006-2007 season as the team beat 3 out of the 4 Big 5 teams they played, all away from Drexel's home court  ; (Drexel did not play La Salle that season). Many writers have called for Drexel's inclusion, and coaches of Big 5 teams have agreed . Regardless of Drexel's absence in the Big 5, they are a member of the City 6 which includes every Big 5 school plus Drexel.