TGIF was an American prime time television programming block that has aired on ABC at various points since the late 1980s. The name comes from the initials of the popular phrase "Thank God It's Friday"; however, the stars of the lineup touted the initialism meaning "Thank Goodness It's Funny." In its various incarnations, the block mainly featured situation comedies aimed at a family audience, and served as a lead-in to the long-running newsmagazine 20/20 (which has been part of ABC's Friday night schedule since September 1987, two years prior to the original launch of TGIF).

The block initially premiered on September 22, 1989, marking one of the first attempts by a major network to brand a programming block (a concept that was concurrently becoming popular among cable networks at the time of its inception), with the goal of encouraging young viewers to watch the entire lineup, instead of just a particular show. The "TGIF" block dominated the ratings in the 18–49 demographic for most of the 1990s. However, ratings began declining during the latter half of the decade due partly to Fridays becoming more common for social outings among segments of the block's key demographic as well as the loss and aging quality of many of the lineup's signature shows, culminating in the original incarnation ending after eleven years on September 8, 2000.

ABC revived the "TGIF" brand on September 26, 2003, with its second run lasting only two seasons, ending on September 15, 2005. On May 15, 2018, the network announced that it would revive the block, with the third incarnation, which has launched on October 5, 2018. This newest incarnation of TGIF consisted of a mix of sitcoms and game shows. The incarnation was short-lived, with the block ending for the third time on September 27, 2019.