Donovan Mitchell attended multiple schools during his high school years. For his first two years, he went to Canterbury School in New Milford, Connecticut, after graduating from Greenwich Country Day School, also in Connecticut. For his junior and senior years, he transferred to Brewster Academy in Wolfeboro, New Hampshire, where he focused more on basketball and gained significant attention from college coaches

. In summary:

• Early high school: Greenwich Country Day School (Connecticut)
• First two years of high school: Canterbury School (New Milford, Connecticut)
• Last two years of high school: Brewster Academy (Wolfeboro, New Hampshire)