The 25 year old has been a stand out performer for the Titans this season, scoring eleven tries as they finished seventh in the table.
Also capable of appearing at outside centre, he started out at Boyne RFC and was a member of the Ireland squad that won the U20s Six Nations Grand Slam in 2007 alongside the likes of Leinster's Cian Healy and Munster's Keith Earls.
At 6ft 2 and weighting in at over 16 stone, his physicality and eye for the try line will make him a valuable addition to Gloucester's back line options next season.
Now preparing himself for a crack at the Aviva Premiership with Gloucester, Monahan admits that he's looking forward to the summer move to Kingsholm.
"It's a fantastic opportunity for me to pit myself against the very best in the English club game.
"Gloucester already have some really talented backs in the squad and it's going to be great for my game to work with them. They've also signed some class players for next season so it's a really exciting prospect.
"I'm genuinely excited about joining such an historic club. Kingsholm is one of the most famous club grounds in the world and the support is second to none. I can't wait to get down there, meet my new team mates and start preseason."