There were clashes between away supporters and stewards and then between small sections of Leeds and Barnsley fans during the 2-0 victory for the Whites at Oakwell.
A Barnsley FC spokesperson said: "Barnsley Football Club and Leeds United Football Club are greatly disappointed by reports of violence at yesterday's game and will be working together to assess the matter."
Leeds added: "Leeds United and Barnsley Football Club are greatly disappointed by reports of violence at yesterday’s game and will be working together to assess the matter."
