This study examined School Quality Assurance (SQA) criteria for enhancing learning achievements in Public Primary Schools (PPSs) in the Arusha region, Tanzania, adopting a concurrent research design under a mixed methodology approach. Researchers used semi-structured interviews and closed and open-ended questionnaires for data collection from 226 respondents. Qualitative data were analyzed using a thematic approach, and quantitative data via descriptive and ordinal regression statistics. The study revealed that unawareness, poor understanding, inadequate utilization, infeasibility, and inflexibility of the SQA criteria harmed learning achievements. The lack of familiarity stemmed from insufficient training and limited accessibility of SQA handbooks among School Quality Assurance Officers (SQAOs) and teachers, resulting in the ineffective implementation of SQA criteria during school assessments. The infeasible and inflexible nature of the criteria failed to address the unique challenges faced by each school. The study found a significant positive relationship between awareness, effective utilization, feasibility, flexibility and sharing of SQA criteria, alongside fair judgments by SQAOs and learning achievements, as their probability values were less than .05. The study recommended in-service training programs on SQA criteria to equip SQAOs, headteachers, and teachers with the necessary skills and knowledge for effectively implementing SQA criteria in the school assessments to enhance learning achievements.