Social media has been widely blamed for amplifying calls to violence and spreading misinformation that contributed to the Jan. 6 attempt to violently overturn the election results.
Democratic Representative Mike Doyle asked the CEOs if they bore some responsibility during the hearing.
Only Twitter Inc CEO Jack Dorsey replied "yes" to the question, but said the "broader ecosystem" had to be taken into account. Sundar Pichai, chief executive of Google parent Alphabet Inc, said the company always feels a sense of responsibility but it was a complex question.
Facebook Inc's CEO Mark Zuckerberg said his company was responsible for building "effective systems." He also said that the rioters and former President Donald Trump should be held accountable.
Lawmakers widely slammed the platforms' approach to false or dangerous content. The three companies have taken steps to curb misinformation but researchers have shown it is still widely present on the platforms.
In the joint hearing, held by two subcommittees of the House Energy and Commerce Committee, lawmakers also questioned the executives on the proliferation of COVID-19 and vaccine misinformation and raised concerns about the impact of social media on children - including asking questions about Facebook's plan to create a version of Instagram for kids.