Robyn Peoples, 26, and Sharni Edwards, 27, became history makers at a ceremony in a hotel in Carrickfergus, Co Antrim, on Tuesday afternoon.
Their marriage came after a landmark law change in the region.
The day marks their sixth anniversary as a couple and they had booked a civil partnership ceremony at the Loughshore hotel months before Westminster MPs passed the legislation last summer.
When it became clear the first marriages could take place in Northern Ireland this week, they changed their ceremony to a wedding.
After a long and high-profile campaign for reform, same-sex marriage was eventually legalised at Westminster by MPs who stepped in and acted on the controversial issue during the powersharing impasse at Stormont.
Ahead of the ceremony, Ms Peoples, a senior care worker from Belfast, said the pair were sending a message to the world that "we are equal".
"Our love is personal, but the law which said we couldn't marry was political," she said.
"We are delighted that with our wedding, we can now say that those days are over.
"While this campaign ends with Sharni and I saying 'I do', it started with people saying 'No' to inequality. By standing together, we've made history."
Ms Edwards, a waitress from Brighton who did not even know the law was different in Northern Ireland until she moved to Belfast from England, added: "We feel humbled that our wedding is a landmark moment for equal rights in Northern Ireland. We didn't set out to make history - we just fell in love.
"We are so grateful to the thousands of people who marched for our freedoms, to the Love Equality campaign who led the way, and the politicians who voted to change the law.
"Without you, our wedding wouldn't have been possible. We will be forever thankful."
While the wedding took place in Co Antrim, at Westminster campaigners were preparing for a celebratory reception to thank those MPs who acted on the issue.
Sara Canning, the partner of murdered author Lyra McKee, who was shot dead by dissident republicans in Londonderry last April, is attending the event organised by Amnesty International and the Love Equality campaign.
"What a wonderful moment in our history," she said.
"This really means so much and has brought me some much-needed light in what has been a dark year," Ms Canning said.
"I know Lyra would have been so overjoyed to see this day. She was a strong advocate for equal marriage and we both took part in the marches organised by the Love Equality campaign.
"Of course, this historic moment is a little bitter-sweet. It had been our dream too.
"Lyra and I should have been an engaged couple now, planning our own wedding day.
"But I am so happy for Robyn and Sharni, the first couple to marry under the new law. We've been in touch in recent days and I'm delighted for them and for all the other couples who will follow."