The main cast of the American TV series Whose Line Is It Anyway? typically includes:

• Ryan Stiles, a permanent performer since the original UK series and throughout the US version

• Colin Mochrie, also a permanent performer from the UK series and consistently on the US series

• Wayne Brady, who joined as a permanent performer from season 2 of the US series onward

• The host role has changed over time: Drew Carey hosted the original US run (1998–2007), and Aisha Tyler has hosted the revival since 2013, although she does not regularly participate in the improv games

In addition to these core performers, the fourth seat is often filled by rotating guest performers, including veterans like Greg Proops, Brad Sherwood, Chip Esten, and others

. The British original featured Clive Anderson as host, with Ryan Stiles, Colin Mochrie, Greg Proops, Josie Lawrence, Tony Slattery, and others as frequent performers

. The show also features improvisational musician Laura Hall, who has been part of the US series for its entire run, providing musical accompaniment for singing games

. In summary, the key recurring cast members of Whose Line Is It Anyway? are Ryan Stiles, Colin Mochrie, Wayne Brady, with Aisha Tyler as the current host, and various guest performers filling the fourth spot