Joseph "Jeph" Loeb III is an American film and television writer, producer, and comic book writer. Loeb has made significant contributions to both the television and comic book industries. He was a producer and writer on the TV series Smallville and Lost, as well as a writer and co-executive producer on the NBC TV show Heroes from its premiere in 2006 to November 2008. From 2010 to 2019, he served as the Head of and Executive Vice President of Marvel Television.

A four-time Eisner Award winner and five-time Wizard Fan Awards winner, Loeb's comic book work includes writing for many major characters, such as Spider-Man, Batman, Superman, Hulk, Captain America, Cable, Iron Man, Daredevil, Supergirl, the Avengers, and Buffy the Vampire Slayer. Much of his work in comics was produced in collaboration with artist Tim Sale.