Middleborough High School is accredited by the New England Association of Schools and Colleges, Inc., a non-governmental, nationally recognized organization whose affiliated institutions include elementary schools through collegiate institutions offering post-graduation instruction and degrees.

Accreditation of any institution by the New England Association of Schools and Colleges (NEASC) indicates that it meets or exceeds criteria for the assessment of institutional quality, which is periodically analyzed through a peer group review process, which happens every ten years. An accredited school is one which has available the necessary resources to achieve its stated purpose and goals through appropriate educational programs. This process also gives reasonable evidence that it will continue to do so in the foreseeable future. Institutional integrity is also addressed through the accreditation process.