DID YOU KNOW? With Doctor Strange set to join the Marvel Cinematic Universe - a universe in which nearly of all the main heroes who have appeared so far have ended up joining the Avengers - people often assume that the sorcerer must be an Avenger too. He isn't, however.
That's not to say that he won't be a member in the live action continuity, but he has never been on the team's roster in the comic books.
In 2008, he joined the team known as the New Avengers, but he has never been a member of the core Avengers team. He has fought alongside them and he did side with them in the Avengers Vs X-Men storyline, however.
He tends to work alone, although he has been a prominent member of the Defenders alongside the likes of Hulk, Silver Surfer, Namor and a load of other heroes - some of whom are totally B-list.
He is also a member of the Illuminati - a group of elite minds (like Mister Fantastic, Professor Xavier and Iron Man) who work behind the scenes to protect humanity from major threats, often through morally questionable means - but an Avenger he is not.