The Crefeld School is an alternative school[1] for students in grades seven through twelve in Chestnut Hill, Philadelphia.

[5] Greenberg, a former teacher at The Miquon School (a private progressive elementary school founded in 1932), created the new upper school partly in response to requests from parents and former students from The Miquon School who wanted the opportunity to continue their schooling in the tradition of progressive education.

[5][6] For the 2023-2024 school year, Crefeld enrolled 91 students in grades 7-12.

[7] Crefeld is not accredited by the Pennsylvania Department of Education.

However, Crefeld is accredited by the Pennsylvania Association of Independent Schools (PAIS).