Frederick Douglass High School, established in 1883, is an American public high school in the Baltimore City Public Schools district. Originally named the Colored High and Training School, Douglass is the second-oldest U.S. high school created specifically for African American students. Prior to desegregation, Douglass and Paul Laurence Dunbar High School were the only two high schools in Baltimore that admitted African-American students, with Douglass serving students from West Baltimore and Dunbar serving students from East Baltimore.

Former Supreme Court Justice Thurgood Marshall (1908–1993) is one of Douglass's most notable alumni. After graduating from Douglass in 1926, Marshall went on to college and law school, passing the bar and becoming a lawyer. Representing the NAACP, he successfully challenged school segregation in the landmark Supreme Court case, Brown v. Board of Education (1954). The Supreme Court ruled that segregated, separate but equal, in public education was unconstitutional because it could never truly be equal.

Due to residential segregation and changes in the demographics of Baltimore, as of 2008 the overwhelming majority of students at Douglass were African American and many were poor. It was one of the eleven lowest performing schools in the state of Maryland.