The actress, who stars in My Week With Marilyn, in cinemas later this month, revealed to Elle magazine: "Men hate my hair."
Williams had her hair cropped while she was in a romance with her Brokeback Mountain co-star Ledger, and has kept it relatively short ever since.
She reveals now: "I cut it for the one straight man who has ever liked short hair and I wear it in memorial of somebody who really loved it."
Williams and Ledger got together during the filming of Brokeback Mountain in 2004, and their daughter Matilda was born in 2005.
Ledger died in January 2008 of a prescription drug overdose in New York.
Williams explains now: "I've really grown into it - I feel like myself with short hair. And it's been a really long time since I had long hair, five years.
"Of course, the only people who like it are gay men and my girlfriends.
"Straight men across the board are not into this hair."
Is Michelle Williams right? Is beauty beyond the realm of women with short hair? Check out our Slideshow of celebrated beauties who have famously gone for the chop, and see if she’s right…