The Dunedin-wide mufti day was organised by the schools' head boys and head girls at one of their regular meetings.
John McGlashan head boy Campbell Garry said the group wanted to tackle a project and decided to help the hospice.
They thought it would be cool to have every pupil in Dunedin in mufti on the same day.
Those schools that could not hold a mufti day tomorrow had either had one last term or would run one later this term, he said.
Columba College head girl Alice Marsh said the hospice was chosen because cancer affected everybody.
Hospice marketing co-ordinator Lyn Chapman said the initiative was "absolutely fantastic".
"I love the fact that young children are now recognising the hospice in our community.
"It's a huge help to us."
About $10,000 was expected to be raised which would go towards computerised drug delivery systems.
These cost $2250 each and allowed patients to safely self-medicate.
