The Big Bang Theory Episode Guide

The Big Bang Theory ran for 12 seasons from September 24, 2007 to May 16, 2019 and produced 279 episodes.

Howard & Bernadette: Key Episodes
The key moments from Howard and Bernadette's relationship including their first date, Howard's proposal, their wedding, and the births of their two children.
Leonard & Penny: Key Episodes
The key moments in Leonard and Penny's relationship including the first time they saw each other across the hall, their first kiss, their first date, breaking up and getting back together, the first time Penny says "I love you", a couple of proposals, their engagement, two wedding ceremonies, and finally Penny getting pregnant.
Sheldon & Amy: Key Episodes
The key moments in Sheldon & Amy's relationship including Howard & Raj setting them up, the signing of the relationship agreement, the first time they said "I love you", them breaking up and subsequently getting back together, the proposal, the wedding and winning the Nobel Prize together.
Christmas Episodes
Celebrate Christmas with Sheldon, Leonard, Penny, Howard, Raj, Amy and Bernadette in these classic Christmas episodes of The Big Bang Theory.