The Whites have been fined £40,000 after a supporter pushed Newcastle boss Eddie Howe during a Premier League game in May.
The incident took place in the technical area at Elland Road and the fan in question was quickly charged with assault by West Yorkshire Police.
He was due to appear before magistrates in July and was later sentenced to 12 weeks in prison and issued a football banning order for six years. Leeds had also already issued their own lifetime ban.
But the club have also now been punished by the FA for the incident as it breached rules over supporter conduct.
Half of the £40,000 fine is suspended until the end of next season and Leeds have been warned with regard to future conduct.
An FA statement read: "Leeds United have been fined £40,000, with £20,000 suspended until the end of the 2024/25 season, and warned as to their future conduct for breaching FA Rule E21.1 at the Premier League game involving Newcastle United on Saturday 13 May 2023.
"Leeds United admitted that they failed to ensure their spectators and/or supporters (and anyone purporting to be supporters or followers) conduct themselves in an orderly fashion and don’t use words or behaviour which are improper, offensive, violent, threatening, abusive, insulting or provocative."