Year 6 winners Forest Primary School and Year 8 winners Les Beaucamps High School came out on top in the Guernsey heats of the de Putron Challenge.
Both schools will represent Guernsey in the final of the inter-island schools quiz in Jersey later this month.
Castel Primary and Les Varendes High School were runners up.
Teams from both age groups answered STEM-based questions, which saw sides creating catapults out of wooden lolly sticks, rubber bands and a spoon.
Every student that took part received a book voucher, and the pupils that came in first and second place took home money for their schools.
Hayley de Putron, a trustee of the Ana Leaf Foundation and Founder of the de Putron Challenge, said:
“Congratulations to Forest Primary School and Les Beaucamps High School for coming out on top in their respective year groups.
As every de Putron Challenge comes around, I continue to be extremely impressed with the level of knowledge our competitors possess.
All of the teams tried their best today, and I hope that their peers, teachers, and all the other teams all developed their knowledge and learnt something today.”
The winning teams from Forest Primary School and Les Beaucamps High School will be going on to compete against the winning Jersey teams, Jersey College Preparatory School and Victoria College, in the final on 21 March.

Guernsey teen set for month-long marathon swim
Guernsey Post introduce new services from early July
Guernsey Waste improves the quality of its free garden compost
Guernsey cat lover to ride the length of Britain in nine days
Unclaimed CI Co-op cash funds community projects
Work to commence on 70 affordable flats and homes in Guernsey
A new tax, more 'proportionate' to wealth, to be put to Guernsey's States
Guernsey gives £75k for Islands Unlimited inter-islands sailings