Social media was flooded with messages Sunday, mostly from women, who tagged their profiles to indicate that they have been sexually harassed or assaulted.
Some men, including Hamilton actor Javier Munoz, also posted the phrase.
A number of allegations have been made against Weinstein and police investigations have been launched in the U.S. and United Kingdom against the corpulent producer.
The campaign, which Milano credited to a friend, came amid a snowballing scandal related to the alleged sexual misconduct of film producer Harvey Weinstein.
Writer Charles Clymer, who has been the victim of rape, took to Facebook to share his views. Some just wrote "me too", while many others described their personal experiences of harassment or assault.
Among the thousands of responses included Lisa J, who posted: "Me, too".
"Honestly, has happened to *every* woman I know".
"We shouldn't have to out ourselves as survivors in order for people to grasp the magnitude of how systemic assault & harassment are", one tweet read.
Milano costarred with Rose McGowan on the show "Charmed".
Milano joined in the boycott, tweeting that Friday would be the first day in over 10 years that she wouldn't tweet. Say you have a father, a brother, a son who can do better.
"It is because of my love for Georgina, India and Dashiell that I haven't publicly commented on this until now". "This is a sick culture". They want the Hollywood industry to change but want to make it more known that sexual harassment is a problem for women everywhere.