Phi Kappa Psi (ΦΚΨ, Phi Psi) is an American collegiate social fraternity founded at Jefferson College in Canonsburg, Pennsylvania on February 19, 1852. There are over a hundred chapters and colonies at accredited four year colleges and universities throughout the United States. More than 114,000 men have been initiated into Phi Kappa Psi since its founding. Phi Kappa Psi and Phi Gamma Delta, both founded at the same college, form the Jefferson Duo.

In the Fall of 1850, a typhoid fever epidemic hit Jefferson College in Canonsburg, Pennsylvania. Many students left school. Among those who remained were William Henry Letterman and Charles Page Thomas Moore. They chose to care for their fellow classmates who were stricken with the contagious disease, and a strong bond was formed. In the following school year, Letterman and Moore decided to found a fraternity based on "the great joy of serving others" that they experienced during the epidemic. On February 19, 1852, Phi Kappa Psi was founded.

The Executive Council of Phi Kappa Psi is composed of the President, Vice President, Secretary, Treasurer, and 6 Archons.