The 20-year-old has only just returned to fitness after sustaining a cruciate knee ligament injury while on loan at Wolves last season and Arsene Wenger was keen to send him out again.
Frimpong has made two appearances for the Gunners in the Capital One Cup wins over Coventry and Reading, but his chances will be limited at the Emirates Stadium and he joins the Addicks until New Year's day.
"We're really happy that he's coming in to join our squad, and we welcome him to the club," Charlton manager Chris Powell told the club's official website.
"We've had our eye on him for a while, and with the busy Christmas period to come, I felt it was right to make sure that we are covered in all areas. We hope that does very well for us in the red or black of Charlton."