The House of Commons voted 383 to 73, a majority of 310, to include the provision in legislation.
The gay marriage ban is a key dispute between the DUP and Sinn Fein, who have struggled for years to reconcile their differences.
A vote to extend abortion access to Northern Ireland also passed with a majority of 233.
The Stormont powersharing administration has not sat for two-and-a-half years, and Labour MP Conor McGinn led the cross-party bid to address the issue at Westminster.
Labour MP Conor McGinn, who put forward the same-sex marriage amendment, has described its passing as "a fantastic victory".
"Having been let down so many times before, LGBT people in Northern Ireland can now look forward to enjoying the same rights as everyone else in the rest of the UK and on the island of Ireland," he said in a statement posted to Twitter.
Mr McGinn said he hopes the Northern Ireland Executive and Assembly will be restored and working by October 21 so that they can introduce equal marriage.
"But if Stormont still isn't functioning by then, the LGBT community in Northern Ireland now know that Westminster will act to ensure equality and respect for all citizens, and finally give them the right to marry the person they love," said Mr McGinn.
Director of The Rainbow Project and member of the Love Equality civic campaign John O’Doherty said the future was "a little brighter" following the vote.
“Parliament has always had the power to legislate for marriage equality in Northern Ireland and we are glad the House of Commons has seen sense and voted to give people in Northern Ireland the same freedoms enjoyed by everyone else in these islands," Mr O'Doherty said.
“All love is equal and we are proud to celebrate this achievement with our community, friends, colleagues and allies from across these islands.
The DUP and some religious leaders believe marriage should only take place between a man and woman, arguing that civil partnerships are an option for same-sex couples.
The party tweeted: "The DUP does not have the numbers in the Assembly to table a Petition of Concern. The DUP cannot stop the introduction of same sex marriage legislation."
Sinn Fein and a coalition of civic society activists believe the change is an issue of equality and human rights.
A proposal aiming to extend abortion access was also approved, by 332 votes to 99.