<p>A School-based Playgroup Quality Assurance Program was developed and trialled in primary schools in a selected region in Australia, based on evidence of quality playgroups contributing to early years development. This research reports the evaluation of the trial of the program, including level of participant usage and satisfaction, contextual factors influencing quality improvement in playgroups, and evidence of improvement to the quality of playgroups. Process evaluation data was collected using questionnaires, and individual or group interviews to ascertain perspectives of playgroup facilitators as end-users of the program, partnership facilitators as coordinators of the program, and assistant regional directors as strategic leaders across schools. Impact evaluation data was collected from playgroup facilitators via an online self-evaluation questionnaire in relation to evidence of changes to the quality of school-based playgroups. Eighteen school-based playgroups participated in the evaluation. Findings demonstrate the program to build confidence of evidence-based quality playgroups and support quality improvements, particularly where there is whole-of-school support and peer collaboration opportunities. Further exploration of ways to support schools to confidently embed culturally safe playgroup environments would strengthen the program, along with the inclusion of a larger sample of schools to further explore its effectiveness in different contexts.</p>