The ad, which has shown in cinemas and online, features Knightley returning home from a film shoot, only to be beaten up by her boyfriend.
Grey is currently talking to the ad watchdog Clearcast about cuts that might allow the ad to be featured on TV.
Alice Shelley, the copy group manager at Clearcast, said: "The broadcasters’ feeling is that it is too hard-hitting for TV, even with a watershed restriction."
Chris Hirst, Grey London's managing director, told ±±¾©Èü³µpk10: "We have been in discussions with Clearcast about showing this ad on TV but we are in no rush.
"We are relying on free media space for this ad, and so far we have not agreed any with any TV channels."
United Kingdom
Keira Knightley Women's Aid ad 'too violent' for broadcasters
LONDON - Broadcasters are refusing to show Grey London's hard-hitting ad for Women's Aid, starring Keira Knightley, due to the level of violence.