The former Rose of Tralee has eschewed the limelight since her five-year relationship with Ryan Tubridy came to an end in 2014.
However, rumours Ms Ní Shúilleabháin (34) was to marry began last April, when she was spotted wearing a diamond ring.
It has now emerged she married last weekend and took to social media to thank family and friends.
"Thank you to our beautiful friends and family who made our wedding so special," she wrote. "We had an absolute ball sharing our vows to each other with you... Here's to continuing to share the love."
The assistant professor of mathematics at UCD posted photographs online, but the identity of her husband remains a mystery.