Teachers Meg Ryan and Sarah Jane Little, who organised the fundraiser, with five students and two dads, shaved their heads in front of the hundreds of people at the event.
The fundraiser, which started out as the kids doing a car wash and a little market, turned out to be a big day with an amazing turnout from the community, Mrs Ryan said.
Mrs Ryan and Mrs Thompson had worked together for 10 years and Mrs Ryan said shaving her head was her way of giving back to a "brave and inspirational" woman. "If people want to throw money at us for doing this, then why not?" she said, though admitted she was nervous and shaking before going under the razor.
She said though the day was not for a happy thing, they tried to make it fun for everyone.
MrsThompson was not at the event, as she was en route to Melbourne for her treatment.
Omokoroa No1 School principal Chris Broadhurst said the day was "beyond imagination".
"It's turned out to be a lot more than we expected. It's a way the children can show appreciation of their beloved teacher."
The work of the children was "phenomenal", he said, with kids selling baking, getting soaked washing car after car, and a girl swam 100 lengths of the school pool, all in an effort to raise money.
Past pupils of Mrs Thompson came to show their support, with one building a small tuktuk and giving people rides in it to raise cash.
"The whole school community is here, even past pupils of Mrs Thompson. It brings everyone together and that's an amazing feeling," Mr Broadhurst said.
Can you help? Donations can be made at the Leanne Thompson Fundraiser Givealittle page.
