David Bradley, editor of SFX magazine, said: "There's no denying Megan Fox is a compelling choice for a new generation of sci-fi fans! She sizzled on screen in Transformers.
"With the high calibre of the runners-up, she's in good company too: science fiction and fantasy films have always benefited from engaging female characters, with Princess Leia being a role model for many."
Megan was fans' clear favourite with 33 per cent of the votes, followed in second place by Halle Berry with 26 per cent of the votes for her role as Storm in the X-Men movies.
Supermodel-turned-actress Milla Jovovich was third with 17 per cent for her performance as Leeloo in The Fifth Element. Star Wars' Natalie Portman, Sigourney Weaver for Alien and Carrie Fisher as Princess Leia were all fourth with eight per cent.
Ed Holden, MSN Movies editor at MSN UK, said: "Sci-fi is full of strong female characters that capture the imagination of the movie-going public. When Transformers was launched just two years ago Megan Fox was an instant hit with fans, and the new trailer for Transformers 2: Revenge Of The Fallen will undoubtedly create even more buzz around Miss Fox before the summer blockbuster itself hits the screens."