Seven men were arrested after violence broke out when West Ham played Chelsea at the former Olympic Stadium.
Scotland Yard said the men were arrested for public order offences following the clash last night (October 26) at the London Stadium, in Stratford.
A further 30 people were issued with directions to disperse under antisocial behaviour legislation ahead of the EFL Cup match, the Metropolitan Police said.
The force said it deployed a "significant number" of officers in the stadium.
Both clubs issued statements condemning the skirmishes, the circumstances of which are under investigation by police.
Missiles including coins and seats were launched between rival fans.
Stewards struggled to maintain segregation behind the Hammers' goal towards the end of the match, which West Ham won 2-1.
The home club said those found "acting improperly" will be banned from fixtures for life.
The London Stadium has been West Ham's home for nine games after leaving the Boleyn Ground in Upton Park in May.
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