Speaking to People magazine at the premiere of Into The Woods, the 65-year-old star said: "I would say our culture is pretty youth-obsessed".
"Especially people that pass 40."
Meryl, who plays the witch in the Disney film, said when she turned 40, she was offered three witch roles.
"I was not offered any female adventurers or love interests or heroes or demons," she revealed. "I was offered witches because I was 'old' at 40."
However, the Hollywood actress, who is considered to be one of the most successful in history, said times have changed.
"That was 25 years ago. Now there's so much more interesting stuff available."
Meryl joins a string of film stars that have called up the entertainment business to stop stereotyping women because of their age.