The incident happened during the game against Portsmouth at The Valley.
The match was halted in the 12th minute as the supporter received treatment.
Sadly, the fan later passed away in hospital.
The club has expressed devastation at the loss and thanked Charlton staff and first responders who “did everything they could” to help.
A Charlton Athletic spokesperson said: “The club are devastated to report that a Charlton Athletic supporter has died following a medical emergency during today’s game at The Valley against Portsmouth.
“The club are grateful to supporters in attendance and the Portsmouth players and staff for their patience and understanding as this tragedy unfolded.
“Everyone at the club sends their heartfelt condolences to the supporter’s family and friends at this incredibly difficult time.”
As a result, the match was postponed.
On Instagram, a spokesperson for Portsmouth FC said: “This afternoon’s match at The Valley has been abandoned due to a medical incident in the crowd.”
