Staff at Chatsmore Catholic High in Worthing, West Sussex, complained that children became rowdy after fuelling themselves with Red Bull and Kick, a high-energy drink.
Anne Ward, the acting head, said: "We were becoming increasingly concerned about the level of inappropriate behaviour, so decided to take action before it became a bigger issue.
"If they want to drink these drinks outside of school, that is an issue for parents, but we would rather they didn't while at school."
A can of Red Bull contains 80mg of caffeine - about the same amount as a cup of coffee. It is said to boost concentration and reaction speeds and to stimulate metabolism - although clearly not to Chatsmore High's liking.
In a statement, Red Bull said that people had different sensitivity to caffeine. "The daily consumption of Red Bull should conform to a person's intake of caffeine, and the same is true for children," it said.