Merchant Taylors' School is an 11–18 boys public day school, founded in 1561 in London. The school has occupied various campuses over its lifetime. From 1933, it has been located at Sandy Lodge, a 285 acres (115 ha) site close to Northwood in the Three Rivers district of Hertfordshire. The school caters for 1100 students between the ages of 11 and 18. The school is now an all-through school from age 3 to 18 after merger with Northwood Prep School in 2015.

In England and Wales, a public school is a type of fee-charging private school originally for older boys. They are "public" in the sense of being open to pupils irrespective of locality, denomination or paternal trade or profession; nor are they run for the profit of a private owner.