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

• Ryan Stiles, a permanent performer since the show's inception.
• Colin Mochrie, also a permanent performer since the beginning and the only person to appear in every episode of the US show.
• Wayne Brady, a permanent performer from the second season onward, except for some episodes.
• Aisha Tyler, who hosts the show since the 2013 revival but does not regularly participate in the improv games, occasionally joining quick scenes.

The show also features a rotating fourth performer and sometimes a special guest who participates in some games

. The original UK version featured some additional notable performers like Greg Proops, Josie Lawrence, and Tony Slattery, but the American version primarily centers around Stiles, Mochrie, Brady, and Tyler as host