Eight officers were injured as fans clashed in Amsterdam before Celtic's champions league match with Ajax.
Police said supporters armed with bottles and sticks fought in Dam Square on Wednesday afternoon.
A spokesman said the majority of the 15 arrested were Celtic fans.
"At the end of the afternoon a large group of Celtic supporters attacked police officers in plain clothes," a police spokesman told the Press Association.
"Eight were injured and one was knocked unconscious. A few of them had broken noses and needed stitches above their eyebrows and on their lips.
"Bottles and sticks were used in the attack which came out of nowhere. There were 15 arrests, mostly Celtic supporters."
"The officers took quite a beating," police spokesman Rob van der Veen told Reuters. "One of the officers was unconscious, another had his nose broken."
Amsterdam police said it expected the number of 15 arrests to rise and that a final figures would be "high".
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