The "Harry Potter" star is the favorite celebrity bait for cyber criminals trying to lure Internet users to download malicious software or give up personal information.
McAfee, a security technology company, says when searching for Watson, there's a one-in-eight chance of landing on a malicious site.
Other celebs on the list include Jessica Biel, Eva Mendes, Selena Gomez and Halle Berry.
This is the sixth time the Intel-owned security technology company has conducted the study, which was last year topped by Heidi Klum. Female celebrities are far more likely to be utilized by cyber criminals: late-night host Jimmy Kimmel was the only male in the top 20.
The Associated Press contributed to this report.