The Big Bang Theory Wiki

Sheldon Lee Cooper's Birthday Party was a birthday party thrown for Sheldon's 36th Birthday in the Season 9 episode "The Celebration Experimentation".


Amy wants to throw Sheldon a birthday party because of what he did for her on her birthday in "The Opening Night Excitation" (S9E11) and because his birthday has never been celebrated, but Sheldon is scared

Sheldon tells Leonard, Penny and Amy that Sheldon doesn't celebrate his birthday because when he was a child, he had terrible birthdays. Anyone Sheldon invited would never come because they didn't like him, but it wasn't quite a problem because he didn't like them, either. But the real problem is his twin sister: For the whole day, Sheldon was tortured by his sister and her friends, but they went too far on their 6th birthday when the girls tricked Sheldon into believing that Batman was coming to the party. He waited by the door for hours and the closest thing he saw to Batman was when a robin flew into the window. And after that, he didn't want another party.

Everyone decides to make it as good as possible. Due to having had encounters with celebrities, Stuart tells the guys that he had met Adam West who played Batman. He gives them West's contact information and they pick him up and bring him to the party.


Apart from Leonard, Penny, Amy, Howard, Raj, Bernadette, Stuart and Adam West being the guests at the party, other guests included Wil Wheaton, Beverly Hofstadter, Barry Kripke and Leslie Winkle. Stephen Hawking, who couldn't turn up, attended via a laptop being held by Amy.

When Sheldon entered the room, he got a little scared and ran off to hide in the bathroom, but Penny went to talk to him. After they came back out, everyone gave Sheldon speeches and later celebrated with cake.


  • Sheldon's birthday was a de facto celebration of the TBBT milestone.
  • Sara Gilbert makes her first appearance on the show as Leslie Winkle in nearly six years, having not been seen or even mentioned since the third season finale "The Lunar Excitation" (S3E23), a span of 137 episodes. This also marks the first time that she appears in an episode with cast members Melissa Rauch and Kevin Sussman.
  • First time Beverly was seen in the same room with Howard and Raj since "The Maternal Congruence" (S3E11).
  • During the party, some things happened for the first time ever that had never happened before this event:
    • First time Barry Kripke meets Bernadette.
    • First time Leslie Winkle meets Amy, Bernadette, Stuart, Wil Wheaton and Beverly, though she may know Kripke from the university.
    • First time that Leonard's mother Beverly is seen with Bernadette, Amy and Stuart.
  • All of Sheldon's living family, excluding his father (George Cooper. Sr.) who is dead, mother (Mary Cooper), brother (George Cooper. Jr.), sister (Missy Cooper), brother-in-law, nephew and grandmother (Constance aka Meemaw) are all absent from the party.
  • All main characters of the show up to this episode, current and former were at the party, except Emily, unfortunately (as Raj had broken up with her earlier on).
  • Bernadette doesn't get a chance to interact with Wil Wheaton at the party.
  • Sheldon's first birthday since he was a kid.