Brentwood School is a selective, independent day and boarding school in Brentwood, Essex, England in the public school tradition. The school comprises a preparatory school, senior school and sixth form, as well as boarding provision for both boys and girls. The school is coeducational, and employs the "Diamond Model". The school is a member of the Headmasters' and Headmistresses' Conference, the IAPS, and the AGBIS.

Brentwood is a town in Essex, England, in the London commuter belt 20 miles (30 km) north-east of Charing Cross and close to the M25 motorway. The population of the built-up area was 55,340 in 2021.