Threesome (stylised as threesome) is a British television sitcom written by Tom MacRae and starring Stephen Wight, Amy Huberman and Emun Elliott. The series is focused around three friends—Alice, Mitch and Richie—who return home from a night out celebrating Alice's birthday and end up having a threesome, which results in Alice getting pregnant. Instead of getting an abortion, the three friends decide to raise the baby as a trio. The series began airing on 17 October 2011 on Comedy Central and Comedy Central HD. It is the first original scripted comedy commissioned by Comedy Central and is produced by Big Talk Productions.

In February 2012, it was confirmed that Comedy Central had renewed the show for a second series. Although this included the possibility of a 22-episode third series, this did not happen.

The show was remade in Finland in 2017, as Kolmistaan.