Anecdotes

Laurie Metcalf, who plays Sheldon's mother Mary Cooper, is the mother of Zoe Perry, who plays Sheldon's mother Mary Cooper on Young Sheldon (2017).

Unlike most TV shows or movies, the food characters eat is real. Their prop master, who previously wanted to be a chef, carefully prepares every meal seen on screen.

Most of the time, Leonard (Johnny Galecki) has no lenses in his glasses.

In the pilot, 100th episode and the final scene of the final episode, Penny (Kaley Cuoco) is wearing the same shirt.

Bob Newhart agreed to appear in the show on one condition, that he have a recurring role. Newhart appeared in six episodes as Arthur "Professor Proton" Jeffries.