Jeremy Corbyn and some other MPs were spotted wearing a white ribbon on their jackets at Prime Minister's Questions on Wednesday.
But what do the ribbons mean?
The white ribbon is part of a campaign to end violence against women - known as the White Ribbon Campaign.
The campaign is organised by men and encourages people to speak out against violence against women by men - especially domestic abuse.
"Violence against women happens more than you think. It’s mostly committed by men. We won’t stand for it," the group's website says.
"We’re a group of men who know that there’s never an excuse for violence against women. We pledge never to condone it, or to stand by when we know it’s happening. We’re part of a worldwide movement."
The campaign has collected over 23,000 pledges of support to "never commit, condone or remain silent about violence against women".
The White Ribbon Campaign is in its 10th anniversary and has cross party support.
