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 Brian George Dr. Koothrappali Guest Star Brian Smith Zack Guest Star Rati Gupta Anu Guest Star Lindsey Kraft Marissa Guest Star Shay Ali Greg Guest Star Chip Chinery Bob Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer Steven Molaro Executive Producer Steve Holland Writer Jeremy Howe Writer Maria Ferrari Writer David Goetsch Writer Eric Kaplan Writer Mark Cendrowski Director