A significant number of Republican lawmakers, 35 out of 211, voted for the probe, defying party leaders' attempts to block the proposal.
The bill, approved in the House by 252-175, now goes to the Senate, where its future is unclear.
Pro-Trump protesters storm US Capitol: In pictures
Supporters of President Donald Trump breached the US Capitol as lawmakers gathered to count electoral votes. Here's a look at some of the chaotic scenes in Washington as rioters clashed with security forces.
Image: Leah Millis/REUTERS
Protesters and police clash
Supporters of US President Donald Trump clash with police officers in front of the Capitol Building in Washington DC on January 6. Congress was holding a joint session to ratify President-elect Joe Biden's Electoral College win over President Trump.
Image: Stephanie Keith/REUTERS
Angry protesters march towards the Capitol
Aggressive pro-Trump supporters rallied outside the US Capitol's Rotunda. Police tried to hold them back, but they breached security and forced their way into the building.
Image: Roberto Schmidt/AFP/Getty Images
Forceful entry
An angry pro-Trump mob breaks into the US Capitol building on January 6, 2021, while Congress holds a joint session to ratify President-elect Joe Biden's Electoral College win over President Trump.
Image: Win McNamee/Getty Images
Guns drawn
With guns drawn, US Capitol police officers watch as protesters try to break into the House Chamber, the inner-most room where legislators had convened to ratify the Electoral College vote.
Image: J. Scott Applewhite/AP Photo/picture alliance
Standoff outside the Senate
Security officials try to hold off the rioters in the hallway outside the Senate chamber as lawmakers on the other side of the door are rushed to safety.
Image: Manuel Balce Ceneta/AP Photo/picture alliance
Taking over the Senate
After breaking through Capitol security, a protester rushes to the middle of the Senate chamber and screams "Freedom."
Image: Win McNamee/Getty Images
Invading the Senate chamber
A rioter manages to break through security, and jumps from the public gallery to the floor of the Senate chamber.
Image: Win McNamee/Getty Images
Taking shelter
People frantically searched for shelter in the House gallery, as the protesters tried to break into the House chamber. According to a White House reporter on the House floor, people were given gas masks that were under the seats.
Image: Andrew Harnik/AP Photo/picture alliance
Protesters move in
Pro-Trump supporters took over the offices vacated by lawmakers who had been rushed to safety.
Image: Saul Loeb/AFP/Getty Images
No holding back
Without police or security officials to hold them back, protesters walzed through the Rotunda and lawmaker's offices. This one carried away the lectern of Speaker of the House Nancy Pelosi.
Image: Win McNamee/Getty Images
Tear gas against protesters
Security forces use tear gas on rioters rallying outside the US Capitol Building.
Image: Andrew Caballero-Reynolds/AFP/Getty Images
Chaos in the Capitol
An explosion caused by a police munition goes off while pro-Trump supporters rally in front of the US Capitol building. Washington police and the national guard have been deployed to disperse the protesters.
Image: Leah Millis/REUTERS
Dispersing protesters
Members of the National Guard and Washington DC police have been deployed to the Capitol to disperse protesters. A city-wide curfew went into effect from 6:00 pm to 6:00 am.
Image: Spencer Platt/Getty Images
13 images1 | 13
What is the proposal?
The bill would establish a 10-member panel commission — with five members appointed by each party — to investigate the attack on the Capitol by supporters of former President Donald Trump.
"This commission is built to work, and it will be depoliticized, and it will get the results we need," House Republican John Katko, who worked with Democrats to craft a deal on the commission, told his colleagues on the floor.
"I urge all of you in the body, all of you on both sides... to set aside politics just this once — just this once."
The commission is set to be similar to a high-profile 2002 panel that probed the September 11 attacks on the US.
What is next for the bill?
The Senate now has the power to either approve or drop the proposal.
The chamber is divided 50-50, with Vice President Kamala Harris typically having the power to break a tie. But at least 10 Republicans would have to join Democrats for the measure to become law.
The Senate Republican leader Mitch McConnell had initially blamed Trump for inciting the attack on the Capitol, which was breached by his supporters seeking to block certification of the election won by Joe Biden.
But by Wednesday, McConnell has changed his mind.
"After careful consideration, I've made a decision to oppose the House Democrats' slanted and unbalanced proposal for another commission to study the events of January the 6th," McConnell said.
McConnell pointed to ongoing law enforcement investigations that have already resulted in more than 400 arrests, adding that a new panel might cause unnecessary overlap.
"It sounds like [Republicans] are afraid of the truth, and that's most unfortunate," House Speaker Nancy Pelosi told reporters.
