The initiative, which is called Time's Up, was announced via a full-page advert printed in the New York Times.
The Hollywood project is described as a "unified call for change from women in entertainment for women everywhere".
It comes in the wake of sexual abuse allegations by high-profile actresses against film producer Harvey Weinstein.
In a "solidarity letter" published on its website, Time's Up says the "struggle for women to break in, to rise up the ranks and to simply be heard" must end, adding: "Time's up on this impenetrable monopoly."