The transition to secondary school is an important educational milestone impacting wellbeing and academic achievement. Students with Autism Spectrum Disorder may be vulnerable during transition however little is known about how Autism Spectrum (AS) traits influence transition outcomes. Generalised estimating equations were used to examine how AS traits were associated with four indicators of successful transition in a school-based sample of 51 students. Higher AS traits were associated with lower quality of life, school belonging and mental health, however the hypothesised decline after school transition was not supported. Characteristics of both the primary and secondary school appeared to be contributing to the wellbeing of students with high AS traits which could be clarified by further investigation with a larger sample.