Boys at a Melbourne high school claim they were told to put on shorts after showing up for their final day of classes wearing the traditional girls' uniform.
But the principal says the issue was not the boys wearing dresses, but that they were too short.
Bentleigh Secondary College year 12 students decided to swap uniforms for the day, in a final statement endorsing the Safe Schools policy of gender diversity.
But what was planned as an empowering message to younger students quickly turned sour.
The students claim boys were removed from class and told to change while the girls were left alone.
Students claim principal Helene Hiotis told them their "stunt" was disrespectful and amounted to indecent exposure.
In a statement to parents, seen by The Age, principal Helene Hiotis said the uniforms were "extremely short and worn unbuttoned, which was deemed inappropriate".
Ms Hiotis said the boys were asked to "tone down their outfits" after complaints from other students about the length of the dresses.
"Not a single student has been disciplined or sent home for wearing dresses to school today," she said.
One student at the school said two boys wearing the school's regulation summer dress were removed from his morning class.
One boy left for the day, while the other stayed and refused to change.
Year 12 students had been asked not to participate in muck-up day activities, but the student said removing people from class was more disruptive than their decision to switch uniforms.
"It was a massive over-reaction," the student said.
"We've always been promoted as a Safe School. We've got posters around the school saying it's okay to wear the other uniform if you want to."
Safe Schools posters previously displayed at Bentleigh Secondary featured a male student in a school dress with the words: "Everyone should be able to wear the uniform that makes them comfortable."
Ms Hiotis said it was an issue of modesty, not gender, and the boys had been told to wear shorts under their dresses.
"This has nothing to do with Safe Schools," she said.
"Bentleigh Secondary College prides itself on being a safe and inclusive environment for all its students."
It's not the first time Bentleigh Secondary has attracted criticism this year.
In March, the school was condemned after ordering two South Sudanese students to take out their hair braids.
The twins had worn the braids since they were babies and said the order was an attack on their African culture.
They were ultimately offered a "school uniform exemption".
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