Purpose <p>Autistic children have an increased likelihood of experiencing anxiety, even in the preschool years. Studies evaluating anxiety interventions in autistic children have tended to focus upon home or community settings. This study expands upon previous work to evaluate whether a parent-mediated intervention for autistic preschool children’s anxiety impacts later school anxiety and school attendance.</p> Method <p>Data for this study comes from a randomised controlled trial of an autism-specific program designed to reduce and/or prevent anxiety in autistic preschoolers; CLK-CUES. In addition to pre- and post-group anxiety measures, the trial included data from parents and teachers one year later, once the children started school. Teacher-reported school anxiety and parent-reported school attendance data were available for the CLK-CUES (<i>n</i> = 15) and control group (<i>n</i> = 13).</p> Findings <p>Children whose parents received CLK-CUES had lower levels of separation anxiety in school and significantly lower non-attendance rates than the control group. This was predominantly due to a significant between-group difference in the number of days missed due to school refusal/distress.</p> Interpretation <p>Findings indicate promise for this autism-specific anxiety program to reduce school anxiety and support school attendance in young autistic children. Further research with larger samples and an extended follow-up is warranted.</p>