The FA have fined West Ham £115,000 after being found guilty of two charges relating to crowd disturbances during win over Millwall.
The Premier League club have also been ordered to pay adjusted costs of £5,000 - but they escaped being forced to play matches behind closed doors.
The violent clashes on August 25 led to 64 arrests and the stabbing of a Millwall fan outside Upton Park, and there were pitch invasions during the Carling Cup match.
West Ham were found guilty of two charges: failure to ensure their supporters refrained from violent, threatening, obscene and provocative behaviour, and failure to ensure their supporters did not enter the field of play.
The FA confirmed the penalty after reconvening on Friday morning to hear and consider West Ham's plea of mitigation.
The club have 14 days to appeal the decision upon receipt of the commission's full written judgement.