Jeremy Gilbert (loosely based on Margaret Gilbert from the novels) is Elena Gilbert's younger brother, later revealed to be her biological cousin.

In the beginning of the series, Jeremy was emotionally damaged by the death of his parents, Grayson and Miranda Gilbert, and he begins to use drugs as a way of coping with his parents unexpected death. He was in love with Vicki Donovan, who uses drugs as well, but she was dating Tyler Lockwood, which causes a rivalry between the two boys. Vicki later breaks up with Tyler and starts a relationship with Jeremy. However Jeremy later witnesses how Stefan Salvatore kills Vicki after Damon Salvatore had turned her into a vampire. Elena, afraid that Jeremy couldn't handle this, asks Damon to make Jeremy forget this and take away his pain. This causes Jeremy to become more stable and to stop taking drugs.