Waynflete School was founded in 1897 by Agnes Lowell and Caroline Crisfield, who came to Portland from the Ogontz School in Philadelphia. During a trip to England, the founders became interested in 15th-century statesman and educator William Waynflete. Bishop of Winchester and Lord Chancellor of England, he founded Magdalen College at Oxford as well as an elementary school at his nameplace, "Wainfleet." From this came the name for the new school in Portland, which opened with forty-nine students, including six boarders.

In an age when private schools in the Portland area were plentiful, Waynflete fast became the school of choice for families seeking strong academic preparation as well as grounding in the arts. And, contrary to popular belief, Waynflete was never entirely an all-girls school, admitting small numbers of boys even from its earliest days.

In 1912, to accommodate the school's rapid growth, Lowell and Crisfield bought the Horace Dudley estate located between Danforth and Spring streets near the Western Promenade. Classrooms were constructed in the nearby stables and carriage house, known today as Founders Hall. The estate's lawns and gardens made a fine playground and an idyllic setting for the annual May Festival and other budding traditions that continue to be celebrated nearly a century later.

Lowell and Crisfield retired from Waynflete in 1924. In the early 20th century, Waynflete adopted the progressive model of education championed by philosopher John Dewey, a movement which emphasized children's physical, social, emotional and intellectual development through "hands-on" learning. It was the vision of then-Waynflete president Dr. Sylvester Judd Beach that the School would pioneer progressive education in the Portland region.

The resiliency of Waynflete would soon be tested through the Great Depression and two world wars, but the next half century marked unprecedented progress at the School nonetheless: boys were admitted for the first time beyond grade four in 1950, and into the high school in 1967; academics broadened with the establishment of summer school in 1957, the dramatic evolution of the language program, full-day Kindergarten, and the Lower School Storer House Program. Campus growth during this time included the Marjorie Robinson Thaxter Library in 1962, the Gymnasium in 1973, The Berle Student Center in 1993, and the Upper School Science Center in 2001.

2009 brought another major addition to the Waynflete campus with the construction of the Arts Center and Joan Sayward Franklin '46 Theater and the renovation of Sills Hall to a second gymnasium. The School continues to move ahead into the 21st century with state-of-the-art technology, a strong commitment to diversity and sustainability, and a continual effort of self-examination that allows Waynflete to provide quality education to our students and a true "Waynflete experience."