Chris Pratt Peter Quill / Star-Lord Zoe Saldana Gamora Dave Bautista Drax the Destroyer Vin Diesel Groot (voice) Bradley Cooper Rocket (voice) Lee Pace Ronan the Accuser Michael Rooker Yondu Udonta Karen Gillan Nebula Djimon Hounsou Korath John C. Reilly Corpsman Dey Glenn Close Nova Prime Benicio del Toro Taneleer Tivan / The Collector Laura Haddock Meredith Quill Sean Gunn Kraglin / On Set Rocket Peter Serafinowicz Denarian Saal Christopher Fairbank The Broker Wyatt Oleff Young Quill Gregg Henry Grandpa Solomon Mousley Meredith's Brother Robert Firth Dr. Fitzgibbon Melia Kreiling Bereet Tom Proctor Horuz Nick Holmes Horuz' Mate Stan Lee Xandarian Ladies' Man Nicole Alexandra Shipley Pretty Xandarian Sharif Atkins Nova Arresting Pilot Brendan Fehr Corpsman Dey's Partner Tomas Arana Kree Ambassador Mikaela Hoover Nova Prime's Assistant Emmett Scanlan Head Riot Guard Dominic Grant Angry Guard Spencer Wilding Mean Guard Alison Lintott Sad Woman with Horns Alexis Rodney Moloka Dar Nathan Fillion Monstrous Inmate Keeley Forsyth Mottled Prisoner Alexis Denisof The Other Enzo Cilenti Watchtower Guard Richard Katz One Legged Prisoner Ronan Summers "Drop the Leg" Guard Ophelia Lovibond Carina Stephen Blackehart Knowhere Dispatcher Ralph Ineson Ravager Pilot Rob Zombie Ravager Navigator (voice) John Brotherton Nova Starblaster Pilot Josh Brolin Thanos (uncredited) Seth Green Howard the Duck (voice) (uncredited)