The year 9 pupils had been punished for wearing school-issued PE shorts rather than trousers on Tuesday 19 July, the hottest day of the year so far.
So Michael Parker, Kodi Ailing, George Boyland and Jesse Stringer, all 14, chose cooler clothing which is part of the official uniform - a pleated navy skirt.
Parker said: “It’s not fair for boys to be roasting in black trousers on the hottest day of the year while the girls can wear skirts.”
His mother Angela, added: “We’re fully in support of the boys.”
Despite not being allowed to wear the school’s branded shorts, the students at Longhill High School, in Brighton, East Sussex were allowed to wear skirts, as they are part of the agreed school uniform.
Wesley Allen, whose son Kodi was part of the protesting group, said the school’s decision to punish the boys for wearing shorts was ‘madness’.
“The shorts he had on have the school logo on them and I think should be allowed to wear them on hot days,” he said.
“The school say they have to wear school uniform and the shorts are.
“I think it’s madness. The boys have done this to prove a point and I think it’s brilliant.
“I don’t think Kodi will wear the skirt all summer but I do think he likes the attention.”
On Tuesday19 July around 20 boys were punished for wearing their gym shorts rather than “regulation uniform”.
Some of the students were sent home and others were kept in isolation and excluded the following day.
Longhill’s headteacher Kate Williams said: “Students have access to water in order to keep themselves hydrated.
“We have made reasonable steps to ensure that classrooms are as comfortable as possible.
“I have high standards regarding uniform and in the warm weather, these high standards have been challenged by approximately 2% of parents/students.”
In a statement, Williams added: “Four male students at Longhill High School chose to wear a skirt to school. Students can choose to wear any part of the agreed school uniform.”
Earlier this year 40 primary schools across the UK made their uniform policy gender neutral, meaning boys would be allowed to wear skirts and girls could dress in trousers.
The Independent reported in June that the change came as part of a government-funded drive for schools to be more open to children questioning their gender identity.