Facebook, Microsoft, Twitter and YouTube have all agreed to a new European Union code of conduct for dealing with hate speech.
The key social media platforms have set themselves a time limit for spotting and deleting offensive content - the companies now must remove messages that express hatred for a group of people or could incite violence within 24 hours of it being posted.
The four have said they will work in conjunction with the European Commission to asses how best to introduce and the new measures.
They have also promised to educate users about the types of content that will not be permitted under the new code, and to share best practices with each other and other platforms.
The EU Commissioner for Justice, Consumers and Gender Equality VÄ›ra Jourová said in a statement:
"The recent terror attacks have reminded us of the urgent need to address illegal online hate speech.
"This agreement is an important step forward to ensure that the internet remains a place a free and democratic expression, where European values and laws are respected".
Monika Bickert, head of global policy management at Facebook, also commented that "there's no place for hate speech on Facebook" and that "our teams around the world review these reports around the clock and take swift action".