They'd all written poems based either on the Queen herself, or events that have taken place during her reign.
The poems were then judged by a panel of leading poets including Poet Laureate Andrew Motion.
Andrew said: "The range and quality of the poems were extraordinary."
The top 50 winners also got their poems published in a special book called Fifty Jubilee Poems.
Around 4,000 kids aged between seven and 18 took part in the competition from schools across the country.
All the entries are to be saved for ever in the Royal Archives at Windsor Castle.