A sequel already was expected, considering their return appears on screen in the end credits of the film.
It’s unclear whether Nicole Perlman, who co-wrote the first “Guardians” with Gunn, will return.
“Guardians” is Marvel Studios’ 10th film since starting to self finance its own projects in 2008, with “Iron Man.”
The Disney-owned studio already has dated a slate of new untitled films through 2019.
Marvel did not comment.
Gunn’s role on the sequel was first reported by The Wrap at Comic-Con in San Diego.