Published Wednesday, 01 January 2014
The 24-year-old proposed to the Danish tennis pro player as the couple rang in the New Year in Australia.
They spread their happy news via Twitter, with the duo posting matching pictures of themselves with a ring and fireworks.
McIlroy, who is golf's current world number six, told his more than 1.8 million followers: "Happy New Year everyone! I have a feeling it's going to be a great year!! My first victory of 2014 #shesaidyes!!"
Wozniacki, who is a former world number one in her sport, also took to Twitter, saying: "Happy New Year everyone! Rory and I started 2014 with a bang! ... I said YES!!!!"
McIlroy travelled to Australia on Boxing Day to be with his 23-year-old fiancée as she prepares to compete in the Australian Open in Melbourne.
They began dating in the summer of 2011.
Their announcement comes after rumours they had split in October.
Last year the Northern Irish star struggled to recapture the form that made him world number one in 2012, but he ended 2013 with a win in Australia, where he later proposed.
© UTV News