Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Kaley Cuoco Penny Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Mayim Bialik Amy Farrah Fowler Actor Melissa Rauch Bernadette Rostenkowski Actor Kevin Sussman Stuart Guest Star Michelle Arthur Mrs. Petrescu Guest Star Parvesh Cheena Marcus Guest Star Bob Stephenson Wendell Guest Star Megan McGown Cynthia Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer Steven Molaro Executive Producer Steve Holland Writer Jeremy Howe Writer David Goetsch Writer Eric Kaplan Writer Maria Ferrari Writer Trevor Alper Writer Mark Cendrowski Director