Aldwickbury School is a 4–13 boys private preparatory school located on the outskirts of Harpenden, Hertfordshire in the United Kingdom. Aldwickbury School was established in 1937, when Kenneth Castle took over as headmaster of Lea House School in Harpenden. At that time, the school consisted of 15 boys.^[2]

In 2022, a total of 364 boys were enrolled at Aldwickbury School.^[3]

The school dates its history from 1937 when Kenneth Castle took over as headmaster of Lea House School in Harpenden. At that time, the school consisted of 15 boys, along-with a small number of girls also attending the school. Castle was later elected to the Incorporated Association of Preparatory Schools as the Head of Lea House in 1943. Aldwickbury Mansion, along with its 14-acre site was purchased following consideration by Castle to use it as a day and boarding school.^[4] To support his vision, Castle invited Brian Chidell to join the permanent staff at the school, encouraging him in becoming his junior partner in the venture. Chidell would later becoming the headmaster of Aldwickbury School following the death of Kenneth Castle in 1960. Chidell purchased the remaining two-thirds of the school shares from Castle wife, Mary Castle, becoming the only proprietor of the school.^[5] In 1969, Aldwickbury School Trust Ltd was established, along with a board of governors to oversee the schools operations.^[6]

In 1967, an existing nursery school provision was invited to join the school, and was incorporated with the school under the Aldwickbury School name later in 1967. During 1969―1979, extensive works were undertaken across the school site, including the construction of new buildings, together with the refurbishment of existing facilities. In 1979, Brian Chidell stepped down from the role of headmaster, with Peter Jeffery becoming the new headmaster in 1979, a position he held until 2003. Vernon Hales was subsequently appointed as headmaster of Aldwickbury School, and Paul Symes took up he post in September 2021. ^[7]

The school consists partly of day pupils and partly of weekly boarders. The school had approximately 65 pupils at its inception, but has over 360 pupils today (including the Pre-Prep).

To date, the school has had only five headmasters:

• Kenneth Castle (1937–1960)
• Brian Chidell (1960–1979; deputy headmaster, 1948–1960)
• Peter Jeffery (1979–2003)
• Vernon Hales (2003–2021)
• Paul Symes (2021 - )

• Tim Rice, lyricist, attended 1950–