Twelve arrests were made at a football match between Leeds United and Derby County on the first day of the Championship season.
Police said the majority of arrests were made when minor trouble broke out at the end of Saturday's game at Elland Road, which Derby won 2-1.
A West Yorkshire Police spokeswoman said the arrests were made for public disorder offences.
She said she was unable to say how many arrests were Leeds or Rams fans.
On Friday, West Yorkshire Police issued a warning that they would take a tough stance against troublemakers this season.