Dozens of people took part in a protest march and picnic over a proposal to convert Hove Park School into an academy.
They set off from the seafront and made their way to Hove Park where they were entertained by the comedian Shappi Khorsandi.
Another comedian, Mark Steel, who has step-children at the school, took part in the protest organised by campaign group Hands Off Hove Park School.
Caroline Lucas, the Green MP for Brighton Pavilion, joined the protesters. She said: “Thanks to the commitment of the teachers, the staff, the pupils and the parents this school has become a great school.
“We don’t need to spoil that and put that at risk by becoming an academy. It’s already doing great work.”
Brighton and Hove City Council has organised a non-binding ballot of parents. The result is expected before the end of term.
The school’s governors are due to decide in September whether to remain as a local authority school or become an academy.