A summer signing in 2011, wing/full-back Morris scored two tries on his Tigers debut against Exeter Chiefs on the opening day of the 2011/12 season and now has seven tries in 26 appearances for the club, including two in last Saturday’s Aviva Premiership victory at London Irish.
Morris follows Graham Kitchener, Steve Mafi, Julian Salvi, Ben Youngs and Tom Youngs in committing his immediate future to Leicester Tigers by agreeing terms on a new contract.
Richard Cockerill, Tigers director of rugby, said: “Niall made a big decision to leave Ireland and come to Leicester last summer and he has been been a very important member of the squad here for the last two seasons.
“He has been improving the whole time with us. He is a good young player who is developing really well and doing a good job for us.”
The 24-year-old Morris previously played with Blackrock College and Leinster in Ireland before moving to Welford Road.
Morris said: “I’m really enjoying my rugby at Leicester and I was happy to agree a contract extension.
“I think I’ve improved a lot as a player with Tigers and that is something I want to continue to do here.
“I’ve had great support from the coaches and the players, and I want to continue to play here and do my best for the club.”