Representatives of the three companies are set to appear before the US House Judiciary Committee on Tuesday, its chairman said.
Conservative Republicans in Congress have criticised social media companies for what they claim are politically motivated practices in removing some content, a charge the companies have reject.
House Judiciary Committee chairman Bob Goodlatte said in a statement that he was pleased the companies will send representatives “to answer questions on their content moderation practices and how they can be better stewards of free speech in the United States and abroad”.
Facebooks head of global policy management Monika Bickert, Youtube global head of public policy and government relations Juniper Downs and Twitters senior strategist Nick Pickles will testify, the committee said.
The committee held a hearing in April on the same topic after representatives of the companies skipped it.
Republicans repeatedly suggested at the hearing that the companies are censoring or blocking content from conservatives, a charge the companies rejected.
Lawmakers from both parties agreed tech companies must remove illegal content like fraud, piracy and sex trafficking but differed on whether they should remove objectionable content.
Goodlatte said “while these companies may have legal, economic, and ideological reasons to manage their content like a traditional media outlet, we must nevertheless weigh as a nation whether the standards they apply endanger our free and open society and its culture of freedom of expression.”
Representative Jerrold Nadler, top Democrat on the committee, said in April “the notion that social media companies are filtering out conservative voices is a hoax, a tired narrative of imagined victimhood.”
Nadler added “conservative commentary, including conspiracy theories of a conservative bent, regularly rank among the most far-reaching posts on Facebook and elsewhere.”
Berin Szoka, president of TechFreedom, said at the hearing that “concerns about Facebooks potential slant are best addressed through other measures, starting with transparency and user empowerment. Ultimately, the best check on Facebooks power today is the threat of a new Facebook disrupting the companys dominance.”
Facebook Chief Executive Mark Zuckerberg told Congress in April that he is “very committed to making sure that Facebook is a platform for all ideas.”
When contacted by Reuters Twitter declined to comment. Facebook confirmed they would participate but declined further comment. Alphabet did not immediately comment.