Catch 21 is an American game show broadcast by Game Show Network (GSN). Created by Merrill Heatter (who also produced the show's predecessor Gambit), the series follows three contestants as they play a card game centered on blackjack and trivia. The show is based on a popular online game from GSN's website and aired for four seasons from 2008 to 2011. It was hosted by Alfonso Ribeiro, with actress Mikki Padilla serving as the card dealer.

The show received positive critical reception as a whole. The series itself was hailed as "a fun game with a solid concept" while Ribeiro was praised as "hands-down, one of the best game show hosts out there." Additionally, the series was acquired by Bounce TV in 2013, with the network hopeful it could "add fuel" to the channel's growing momentum. GSN revived the series on October 14, 2019, with Ribeiro returning to host and Witney Carson as the card dealer. As of 2021, reruns air on its sister channel GetTV.