Commons Speaker John Bercow said the House must "convene without delay" and that he would be consulting party leaders "as a matter of urgency".
He welcomed a ruling by the Supreme Court that Prime Minister Boris Johnson's decision to suspend parliament was unlawful.
In a statement, Speaker John Bercow said: "I welcome the Supreme Court's judgement that the prorogation of Parliament was unlawful.
"The judges have rejected the Government's claim that closing down Parliament for five weeks was merely standard practice to allow for a new Queen's Speech.
"In reaching their conclusion, they have vindicated the right and duty of Parliament to meet at this crucial time to scrutinise the executive and hold Ministers to account.
"As the embodiment of our Parliamentary democracy, the House of Commons must convene without delay. To this end, I will now consult the party leaders as a matter of urgency."
The Supreme Court ruled this morning that Prime Minister Boris Johnson had acted unlawfully when he advised Queen Elizabeth to suspend parliament weeks before Brexit.
The suspension was therefore void.
The ruling paves the way for legislators to return to parliament, where Johnson has no majority.
It could give lawmakers, most of whom are opposed to leaving without the EU without a divorce agreement as he has threatened to do, further opportunity to impede his strategy.
"The decision to advise Her Majesty to prorogue parliament was unlawful because it had the effect of frustrating or preventing the ability of parliament to carry out its constitutional functions without reasonable justification," Supreme Court President Brenda Hale said.
"Parliament has not been prorogued. This is the unanimous judgment of all 11 justices," she added. "It is for parliament, and in particular the speaker and the (House of) Lords speaker, to decide what to do next."
Parliament was prorogued from September 10 to October 14. The prorogation was approved by Queen Elizabeth, Britain's politically neutral head of state, on the advice of the prime minister.
Some lawmakers, including those thrown out of Johnson's Conservative Party for rebelling against his Brexit plans, had said he should resign if he was found to have misled the queen.
