Greely High School is a public high school for grades 9 to 12 located in Cumberland, Maine, United States. The enrollment is approximately 715 students. It also has a professional teaching staff of 64 and 50% of the teachers have advanced degrees. Greely High School is a part of Maine School Administrative District 51, which serves the towns of Cumberland and North Yarmouth. Renovated and added onto over the years, the building originally opened in 1868. The school completed a 10-million-dollar addition/renovation in 2009. Another addition completed in 2018 added a new auditorium to the school. It adopted the International Baccalaureate (IB) program in 2009.

Greely was founded in 1868 with money granted in the will of Eliphalet and Elizabeth Greely. Greely was originally private and known as the Greely Institute until a 1953 town meeting voted to make it a free school.

This article's list of alumni may not follow Wikipedia's verifiability policy. Please improve this article by removing names that do not have independent reliable sources showing they merit inclusion in this article AND are alumni, or by incorporating the relevant publications into the body of the article through appropriate citations. (May 2022)

• Hanley Denning - Founder of Charity Safe Passage/Camino Segura
• Ben True - Professional runner
• Bezabeh "Buggs" Mendelsohn - Record breaking Ethiopian soccer and lacrosse player

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  Wooden version of seal
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  Printed version of seal

• Greely High School website