Police said a male had been ejected from the John Smith’s Stadium and had his flag seized as a result of the gesture, thought to be a reference to the two United fans stabbed to death before a match in Istanbul in 2000.
Christopher Loftus and Kevin Speight were stabbed during street clashes the night before Leeds played Turkey’s Galatasaray in the second leg of the Uefa Cup semi-finals.
Ali Umit Demir was found guilty of murdering both men and sentenced at a court in Istanbul.
Whites fans were calling for action to be taken after the Turkish flag was spotted during the televised game, which Huddersfield won 2-1 with a late goal from Michael Hefele.
In the aftermath of the winner both managers were sent to the stand after both benches got involved in an altercation.
One fan wrote in a message on Twitter to the Football League: “Hope your going to be taking action against Huddersfield for allowing there fans in the ground with a Turkish flag!”
West Yorkshire Police’s Leeds United Twitter account wrote in response to another message: “Male has been ejected from the ground and flag seized. We will be visiting him this week to deal.”