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 Beth Behrs Nell Guest Star Walton Goggins Oliver Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer Steven Molaro Executive Producer, Writer Eric Kaplan Writer Steve Holland Writer Tara Hernandez Writer Maria Ferrari Writer Mark Cendrowski Director