Chris Pratt Peter Quill / Star-Lord Zoe Saldana Gamora Dave Bautista Drax the Destroyer Vin Diesel Baby Groot (voice) Bradley Cooper Rocket (voice) Kurt Russell Ego Michael Rooker Yondu Udonta Karen Gillan Nebula Pom Klementieff Mantis Sylvester Stallone Stakar Ogord Elizabeth Debicki Ayesha Chris Sullivan Taserface Sean Gunn Kraglin / On-Set Rocket / On-Set Adolescent Groot Tommy Flanagan Tullk Laura Haddock Meredith Quill Aaron Schwartz Young Ego Facial Reference Hannah Gottesman Sovereign Chambermaid Ben Browder Sovereign Admiral Luke Cook Zylak's Frenemy Evan Jones Retch Joe Fria Oblo Terence Rosemore Narblik Jimmy Urine Half-Nut Stephen Blackehart Brahl Steve Agee Gef Blondy Baruti Huhtar Richard Christy "Down There!" Rob Zombie Unseen Ravager Sierra Love Robot Courtesan Kendra Carelli Robot Courtesan Seth Green Howard the Duck (voice) Molly C. Quinn Howard's Date Michael Rosenbaum Martinex Rhoda Griffis Sneeper Madame Stan Lee Watcher Informant David Hasselhoff The Form of David Hasselhoff Mac Wells Officer Fitzgibbon Jim Gunn Sr. Weird Old Man Leota Gunn Weird Old Man's Mistress Elizabeth Faith Ludlow Easik Mother Wyatt Oleff Young Peter Quill Gregg Henry Grandpa Quill Ving Rhames Charlie-27 Michelle Yeoh Aleta Ogord Miley Cyrus Mainframe (voice) (uncredited) Jeff Goldblum En Dwi Gast / Grandmaster (uncredited) Fred Galle Sovereign Leader (uncredited) Kelly Richardson Daisy Kiu (uncredited)