Southminster School is fully accredited by the Southern Association of Colleges and Schools Council on Accreditation and School Improvement (SACS CASI). SACS CASI, newly renamed as AdvancED, is a nationally and internationally recognized accrediting agency. Additionally, SACS CASI is recognized by the Texas Education Agency (TEA) as an accrediting institution of high standards. Southminster School received accreditation from SACS CASI during the first year of eligibility. Following a review of the completed self-study report developed by the Accreditation Team, and observations in both the elementary and preschool, Southminster School was awarded full accreditation. Southminster School believes the ongoing self-evaluation and reporting that is required to maintain accreditation status serves to ensure that all elements within the school are regularly assessed and improved to continually meet the highest educational standards.

Southminster School renewed its membership with the Association of Christian Schools International (ACSI), the National Association for the Education of Young Children (NAEYC), the National Association of Independent Schools, and the Houston Area Independent Schools (HAIS). These memberships allow the teachers and the school to receive updates to standards for preschool and elementary education, participate in special workshops, and receive research information pertaining to items like teacher retention, child development, and development to name a few.

Southminster School is considered a school in good standing and is recognized as a member school by the ACSI, NAEYC, NAIS, and HAIS boards.