This study aimed to identify potential modifiable factors prior to early intervention that are associated with better adaptive skills in children with autism spectrum disorder. This cross-sectional study recruited patients with autism spectrum disorder, aged 5-12 years from two tertiary developmental programmes in Singapore. Demographics, family socio-economic status and early intervention details were collected. The primary outcome was the Vineland Adaptive Behaviour Scales Adaptive Behaviour Composite score. Multivariate linear regression analysis was done. The sample (N = 193) comprised 84% males with a mean age of 6 years and 7 months. Mean age at diagnosis was 35.5 months and mean Vineland Adaptive Behaviour Scales Adaptive Behaviour Composite standard score was 76.5. Mean waiting time for early intervention was 6.2 months with a mean intensity of 8.0 h/week. Waiting time for early intervention was a negative correlate of the Vineland Adaptive Behaviour Scales Adaptive Behaviour Composite score after controlling for other variables ([beta] = -0.74, p = 0.04). Significant correlates also included paternal education ([beta] = 5.44, p = 0.03) and the presence of financial difficulties in the family ([beta] = -5.98, p = 0.04). Waiting time for early intervention is a modifiable risk factor that may be addressed during service planning to potentially improve adaptive skills in autism spectrum disorder. Children from low socio-economic status families may be at risk for poor functional skills and will benefit from targeted intervention plans.