Marvel fans have long been speculating when James Gunn’s third installment to the Guardians of the Galaxy franchise would be released and now, thanks to director/screenwriter James Gunn himself, we know when Guardians of the Galaxy Vol. 3 will be released! 2020!Marvel Fans have long been speculating when James Gunn’s third installment to the Guardians of the Galaxy franchise would be released and now, thanks to Gunn himself, we now know when Guardians of the Galaxy: Vol. 3 will be released.