The 20-year-old England youth international returned from a long spell on the sidelines in September, and made a couple of first-team appearances for the Gunners in the Capital One Cup victories over Coventry and Reading.
But Arsene Wenger has decided, with Jack Wilshere also recently reinstated to the first-team squad, Frimpong's chances of playing regular football at the Emirates Stadium would be limited, and the youngster would stand a better chance of first-team football elsewhere.
Frimpong joins Charlton, until the New Year initially, and will play under Addicks boss Chris Powell. The south London side won promotion as League One champions last season, and have begun their first campaign back in the Championship in reasonable form - they currently sit 14th with 23 points from 17 games.
Frimpong spent seven months on the treatment table, after damaging his cruciate ligament in his right knee while on loan at Wolves in February.
Last season, the gritty midfielder featured 14 times for the Gunners before the New Year, but Wenger decided it would be best to further his footballing education away from north London.
The Ghana-born youngster joined Arsenal as a schoolboy, and played an important role in the cub's 2009 FA Youth Cup-winning team. But with Wilshere, Mikel Arteta, Santi Cazorla, Francis Coquelin and Aaron Ramsey ahead of him, Frimpong finds himself well down the pecking order.