The survey was conducted in honor of Administrative Professionals Day, which is April 21, the Web site said.
More than 31 percent of 20,766 respondents voted for Hathaway's portrayal of Andrea Sachs, the second assistant to powerful Miranda Priestly, the ruthless editor in chief of Runway magazine in "Prada."
Coming in at No. 2 with 27 percent of the vote is Dolly Parton's character in "Nine to Five," followed by Julia Roberts' character from "Erin Brockovich" with 21 percent at No. 3, Gwyneth Paltrow's character in "Iron Man" with 15 percent at No. 4 and Maggie Gyllenhaal's character in "Secretary" with 6 percent at No. 5, the Web site said Wednesday.