The contributions of Executive Function (EF) to academic achievement in children with Autism Spectrum Disorder (ASD) are not well understood. Academic achievement and its association with EF is described in 32, 9-year-old children with ASD. EF at age 6 and 9, and academic achievement at age 9 were assessed as part of a larger longitudinal study. Better performance on a Spatial Reversal task but not A-not-B with Invisible Displacement at age 6 was associated with better math achievement at age 9. No relationship was found between these EF measures at age 6 and reading or spelling achievement at age 9. Future studies are needed to explore whether improving early EF skills can increase math achievement in children with ASD.