Thompson, comfortable in attack or wide midfield, has signed a two-year deal with Wycombe after his deal at Notts County expired.
Wycombe boss Gareth Ainsworth told the club’s official website: “Garry is a fantastic professional who will score goals and bring a new dimension to our attack, and I’m delighted we’ve been able to sign him.
“He’s got great experience, he’ll be an important character around the dressing room and his record speaks for itself in terms of what he has achieved in his career.”
Thompson finished last season as Notts County’s top goalscorer with 12 in 46 appearances.
The 34-year-old started out at Morecambe and spent four years at Scunthorpe before joining Bradford, with whom he won promotion to League One and reached the League Cup final.