Saint Mark School is accredited by Cognia through June 2027. In accordance with standards set by the Archdiocese of Baltimore, St. Mark School met the requirements established by the Cognia Accreditation Commission and Board of Trustees and was thereby accredited by the SACS Council on Accreditation and School Improvement.
In May of 2013, Maryland Association for Environmental and Outdoor Education awarded St. Mark Green School Status. The Maryland Green School Award Program is framework for a holistic, integrated approach to authentic learning that incorporates local environmental issue investigation an professional development with environmental best management practices and community stewardship. St. Mark School renewed its Green School status in 2021.