Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Kaley Cuoco Penny Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Melissa Rauch Bernadette Rostenkowski Actor Mayim Bialik Amy Farrah Fowler Actor Kevin Sussman Stuart Guest Star Margo Harshman Alex Jensen Guest Star Josh Brener Dale Guest Star Kate Micucci Lucy Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer Eric Kaplan Writer Steve Holland Writer Steven Molaro Writer Maria Ferrari Writer Adam Faberman Writer Mark Cendrowski Director