Col. Zadok Magruder High School (#510) is a secondary public school located in unincorporated Montgomery County, Maryland, near Redland.

Magruder is named for Colonel Zadok Magruder, a Revolutionary War patriot and farmer. He was colonel in command of part of the Maryland militia and helped establish Montgomery County's government in 1776. The school is called simply "Magruder".

The school first opened in 1970 at 149,533 sq ft (13,892 m²), with 8th, 9th and 10th graders. In 1971, the same student body became 9th, 10th and 11th graders. The first graduating class was the Class of 1973 and numbered approximately 300.

Major additions were added in 1974 (69,000 sq ft (6,400 m²)), 1994 (47,151 sq ft (4,380 m²)), and 2000 (31,178 sq ft (2,897 m²) of additions, 10,519 sq ft (977 m²) of renovation of the 1994 addition, and demolition of 1,384 sq ft (129 m²) of the 1994 addition). The building now totals 295,478 sq ft (27,451 m²).

Magruder has an International Studies Partnership with Hage Geingob High School in Windhoek, Namibia.