Lance arrives at Sixways having recently featured for Western Force in their 2017 Super Rugby campaign.
A two-time Super Rugby winner, with Queensland Reds in 2011 and New South Wales Waratahs in 2014, Lance is an experienced stand-off who will provide further competition for the number ten jersey at Warriors.
The 27-year-old starred for Perth Spirit in their 2016 title-winning National Rugby Championship campaign before being called up to the Wallabies touring squad.
After being named on the bench last winter for Australia against France, Wallabies Head Coach Michael Cheika tipped Lance to make his Test debut but an unfortunate injury sustained for a Wallaby XV against the French Barbarians saw him condemned to the sidelines.
Lance also represented New South Wales Country Eagles where he was named as National Rugby Championship Player of the Season in 2015.
Warriors Director of Rugby Gary Gold said: “Jono is a player who’s got vast experience at the top level having won Super Rugby titles with different clubs.
“He will help drive the competition for the number ten jersey and we’re looking forward to seeing what he has to offer.”
Lance added: “I’m really excited about the opportunity to represent Warriors in the Aviva Premiership.”