Saint Mary School is part of the Archdiocese of Los Angeles and is accredited by both the Western Catholic Education Association and the Western Association of Schools and Colleges.  The last accreditation review occurred in 2019 and resulted in a full-term accreditation.

The WCEA accredits Catholic elementary and secondary schools in nine western states (26 Archdioceses) and the US Territory of Guam.  WCEA co-accredits and is in partnership with regional agencies (WASC,  NAAS, NCA, CASI) and two private agencies (CAIS and HAIS).  WCEA began in 1957 in San Francisco and has a long successful history of assisting school improvement through the accreditation process.