It will be something of a homecoming for the 25-year-old, who was born in Townsville and grew up in Rockhampton, playing his junior football with Norths and Brothers before being signed by the Penrith Panthers.
After winning player of the year honours for the Central Capras in the Intrust Super Cup in three straight years (2010-2012), Glasby made his NRL debut for the Storm in round 16 last season and has now played a total of seven NRL matches.
He was selected in the Queensland Residents squad earlier this year.
"We're very happy that Tim has decided to come to the Cowboys to continue his NRL career," Cowboys general manager - football Peter Parr said.
"He's someone who has impressed us with his ability at the Intrust Super Cup level and then in the NRL when he's had his chances at Melbourne."Like