The vote was held by Rifftrax, a site dedicated to fun-poking alternate commentaries to movies as performed by former Mystery Science Theater 3000 cast members Mike Nelson, Kevin Murphy and Bill Corbett.
Rifftrax polled over 500,000 of its users, and the Robert Pattinson and Kristen Stewart-starring movies were named as the worst ever by over 35,000 people.
The website said of the teen saga: "There's a lot to cover in this vast, sprawling film series so let us try to boil it down for you: 'Mumble mumble mumble moon eyes. Mumble mumble mumble mumble lay in a field. Mumble mumble mumble perv on a baby. Mumble'."
Batman and Robin was runner-up with over 29,000 votes. Also featuring in the top ten were Catwoman, Spiderman 3, Super Mario Bros, Battlefield Earth and The Last Airbender.
The final part of the Twilight series, The Twilight Saga: Breaking Dawn - Part 2, was released last month to mixed reviews, but also to the eighth-biggest opening weekend in US cinema history.
Watch the trailer for The Twilight Saga: Breaking Dawn - Part 2 below:
Photo gallery - The Twilight Saga in pictures: