Police were called in after a string of red-headed schoolchildren were attacked by fellow pupils for having ginger hair.
The assaults, apparently inspired by an episode of the cartoon South Park, took place at the Wingfield Academy in Rotherham last week.
Fans of the cartoon came up with "Kick a Ginger" day, which has been cited as the reason for a number of assaults in recent years.
South Yorkshire Police said the force was alerted to the assaults and an officer had given "words of advice" to those involved.
The school said that the attacks were "deplorable acts" and that students had been "strongly reprimanded".
A South Yorkshire Police spokesman said: "The force was made aware of incidents last week at Wingfield Academy, Rotherham, where a small number of pupils suffered minor injuries.
"Following national guidelines, the school took the lead and dealt with the matter. Police did not investigate.
"However, one of our partnership-based young people officers has given words of advice to those involved.
"In the next few weeks he will also speak at a number of school assemblies to warn of the dangers regarding discrimination and violence."
A spokesman for the school said that pupils had been warned that the attacks would not be tolerated.
He said: "These deplorable acts, done in the name of singling innocent people out, have no place in our school and as soon as it was brought to my attention that such acts had taken place in our school, we acted swiftly to deliver a strong message.
"The pupils involved in carrying out these acts of violence have been strongly reprimanded and a school-wide warning has gone out that any future acts of violence, carried out in the name of discrimination, or any other reason, will be met with a similar strong and decisive action.
"Wingfield Academy has a long and proud history of supporting our students and ensuring that they have a safe environment to learn in, where they can feel secure to come every day and know that they have the staff's support, which makes what happened recently even more sickening."