Deerfield Academy is a private, coeducational boarding school located in Deerfield, Massachusetts. It is a four-year college-preparatory school with approximately 600 students and about 100 faculty, all of whom live on or near campus.

Deerfield is a member of the The Ten Schools Admissions Organization, as well as the G20 Schools group.

In 2007, Deerfield's endowment was valued at $415 million, or roughly $680,000 per student. Tuition is $37,756 for boarding students and $27,642 for day students. The acceptance rate for the 2007-2008 year was 16%.

Deerfield was never affiliated with a religion, but attendance at Congregationalist Church services was required of boarding students until the 1970s and school meetings included the singing of Christian hymns. Deerfield Academy was founded in 1797 when Massachusetts Governor Samuel Adams granted a charter to found a school in the town of Deerfield. The academy quickly established itself as one of the finest schools in the new republic, drawing boys from prominent families across New England. The school was co-ed since its inception and it was run by a series of prominent headmasters including the infamous author Horatio Alger. The school produced influential men that occupied many congressional and gubernatorial seats in New England. By the end of the 19th century, the shifting trends in industrialization had left rural Deerfield behind. The economic hardhsips of the times impoverished local farmers and drove them away to the wealthy cities. The board of trustees was considering closing the Academy, as there only remained nine students. These were the school's darkest times. With little support from local farmers and a dire economic situation, the 100-year old school was on the brink of collpase.

In the early twentieth century, Deerfield's fortunes rose with the appointment of Frank Boyden as Headmaster. He quickly re-organized the school and provided it with a sound financial basis. He recruited students actively from local farms and towns, promising the parents that their boys would be successful. Boyden had great confidence in the value of athletics as a component of education. He often played on the varsity squads when there was a lack of players. He attracted and trained many teachers that would become masters and keep long loyalties to the academy. The prestige enjoyed by the school today is a direct result of the foundations he laid over seven decades, including training scores of men as teachers and headmasters in their own right. His success would not have been possible without the support and assistance of his wife, Helen Childs Boyden. After 66 years of service, Frank Boyden retired in 1968. Boyden's long career and legacy at Deerfield are reviewed in The Headmaster, (1966) by Deerfield alumnus John McPhee.

In 1989, the Academy reestablished co-education, which Boyden discontinued in 1943.

Eric Widmer '57 served as headmaster from 1994 to 2006. He stepped down in June 2006 and soon after assumed the position of Founding Headmaster at King's Academy in Madaba, Jordan, a school inspired in part by HM King Abdullah II 1980's Deerfield years. It opened in the fall of 2007.

The current Head of School, Dr. Margarita O'Byrne Curtis, previously Dean of Studies at Phillips Academy, is the first female to hold the position. The students call her Margarita out of affection.

The new Koch Center for Science and Technology, named after David H. Koch opened in 2007.