Sorry if theres a transfers thread already open but said id start one.
Henderson is moving to French club Montauban after agreeing a three-year contract.
A popular figure with Glasgow supporters, Henderson will leave after nine seasons with the Scottish team.
"My Glasgow contract is up at end of season," Henderson told The Scotsman.
"And I have always wanted the challenge of playing somewhere else some time in my career, so last summer I thought if things didn't go my way this season I'd think about trying that now.
"I feel very lucky to have played professional rugby for my home team for nine seasons, and I've always been very proud to represent Glasgow, but if I'm going to leave I don't want to go when I'm at the very end.
"I want to go when I still have some good rugby in me and can make a good impression there, and my hope is that a change of club and coaching, and a different lifestyle, might give me what I need to get back to my best and back into the Scotland team."