The loose forward has made 83 Super Rugby appearances for the Highlanders and Reds as well as winning the 2011 Rugby World Cup with the All Blacks among 31 appearances for his country.
He played 15 matches for the Reds this season. He topped the tackle count and ranked third for carries at the Reds, while only Sharks lock Marco Wentzel stole more lineouts from opposition throws in Super Rugby than Thomson.
Thomson played alongside compatriot and fellow former All Blacks Tamati Ellison.
"At this stage of my career, I wanted to continue to play Rugby at a high level and it was important to be in an environment that best fits my needs, that I feel can get the best out of me and where I believe I can contribute the most," Thomson said.
"Having played against the Rebels for a number of years, I've seen some real development; the style they play and the direction the Club's heading is exciting. I think my game will fit well with the Rebels and allow me to play some quality football, which I am still very much driven to do."
