The Taft School is a private coeducational school located in Watertown, Connecticut, United States. It enrolls approximately 600 students in grades 9–12.

The school was founded in 1890 as Mr. Taft's School (renamed to The Taft School in 1898) by Horace Dutton Taft, the brother of U.S. President William Howard Taft. Horace Taft's friend Sherman Day Thacher (the founder of California's Thacher School) inspired Taft to start his own boarding school. The school was initially headquartered in Pelham Manor, New York, but moved to Watertown, Connecticut in 1893.

Along with Lawrenceville, Groton, Milton, and its athletic rival Hotchkiss, Taft was one of the first New England schools founded during the great boom in boarding schools at the turn of the twentieth century. In the school's first generation, around half of the student body came from Connecticut and New York. However, Horace Taft came from a famous Ohio political family, and the school developed a reputation for preparing children of the Midwestern gentry for Yale's entrance examinations. In 1928, around 50% of students came from the Mid-Atlantic, 32% from New England, and 11% from the Midwest. 77% percent of Taft graduates between the years of 1920 to 1924 attended Yale.

The school opened in Pelham Manor with ten boarding students, seven day students, and three teachers (including Horace Taft). The subsequent year, the number of boarding students increased to twenty while the day student population grew slightly and the school rented four buildings instead of two. By the end of the school's first year, Horace Taft realized that its current location and facilities were inadequate for the kind of school he envisioned. He leased a former hotel in Watertown called the Warren House and moved the school there in the summer of 1893. The Warren House was renovated to better fit an academic facility and was a part of the school until it was demolished in 1930.

In the late 1920s, Manhattan financier Edward Harkness donated $500,000 to launch a $2 million capital campaign for the school, enabling the construction of new campus buildings.

Horace Taft served as headmaster for 46 years. When he retired in 1936, Time described him as "the grandest" of prep school headmasters; he continued to teach civics at the school until his death in 1943. He was succeeded by Paul Cruikshank, who led the school for 27 years. In 1963, John Esty became headmaster and introduced the Independent Studies program the following year; he also oversaw the admission of the school's first female students in 1971. Lance Odden served as head of school from 1972 to 2001, followed by William MacMullen '78 from 2001 to 2023. The current head of school is Peter Becker '95.

In the 2023–24 school year, Taft enrolled 580 students in grades 9–12, including 100 freshmen (in academy jargon, "lower mids"), 145 sophomores ("mids"), 155 juniors ("upper mids"), and 180 seniors ("seniors").

That year, 82% of the student body lived on campus. 45% of students identified as people of color and 18% came from abroad. 35% of students were on financial aid; 7.6% were on full scholarships; and 55% had previously attended public schools.