The effects of environmental factors [including Socio-Economic Status, Cultural Capital, and Social Capital (Socio-Cultural Level) of both parents] on the Vineland-II adaptive behavior dimensions of toddlers with autism spectrum disorder (ASD), in addition to individual factors, was investigated in 148 Italian toddlers (82% males), aged 18 to 37 months with ASD. Toddlers' age and Griffiths Mental Development Scales general development affected all of the adaptive behavior dimensions, with negative and positive associations, respectively. The Child Behavior Checklist comorbid conditions were negatively associated with some adaptive behavior dimensions while the ADOS-2 Social affect only with the communication dimension. Mothers' and fathers' specific Socio-Cultural Level dimensions were positively associated with toddlers' specific adaptive behavior dimensions with the same magnitude as comorbid conditions.