Simon Gratz High School Mastery Charter, formerly Simon Gratz High School is a secondary school in Philadelphia, named after Simon Gratz (1840-1925), a member of the Philadelphia Board of Education. Originally a public high school operated by the School District of Philadelphia, Gratz has been operated as a charter school by since September 2011. Students from the previous public school's enrollment area are eligible to attend. It is the fifth Philadelphia high school operated by Mastery.