High dosage of early intervention is critical to language skill development in young children with autism spectrum disorders (ASD) (Dawson et al., 2010) and including parents is a cost-effective approach to maximize intervention dosage. However, parent-mediated interventions have inconsistent effects on parent and child outcomes (Oono, Honey, & McConachie, 2013). This variability is likely because parents do not have the same training as clinicians and little effort has been spent examining parent characteristics that may influence their ability to implement different types of intervention strategies. Given the known cognitive, personality and language features (Broad Autism Phenotype, BAP) present among many parents of children with ASD, examining the relationship between BAP traits in parents and their implementation of different parent-mediated intervention strategies is an important first step in identifying potential sources of variability in parent-mediated interventio outcomes. The objective of the proposed study is to examine how BAP traits influence parent use of language intervention strategies and subsequent child language skills. The central hypothesis is that the parental BAP traits will be associated with: (a) differential use of languag intervention strategies and (b) child language skills. The specific aims include determining the extent to which: (a) BAP traits and type of parent-mediated intervention are associated with mother use of language intervention strategies and subsequent child language skills, (b) BAP traits moderate the relationship between intervention type and mother use of language intervention strategies, and (c) mother social cognitive skills are associated with their use of language intervention strategies and their children's language skills. The proposed study will enroll 108 children with ASD 18 - 36 months old and their mothers. Mother-child dyads will be randomly assigned to one of two parent-mediated intervention strategies that are contrasted in their theoretical approach (responsive-developmental, directive-behavioral). Mother-child dyads will be assessed before randomization (pre-test), after intervention (post-test) and 3 months after the end of intervention to monitor maintenance. Children in both groups will receive 8 weekly intervention sessions at home using the same experimental procedures. The proposed research is significant because it will be the first examination of the impact of BAP traits on bot parent and child outcomes of two different parent-mediated intervention strategies (directive, responsive). Understanding the effects of BAP traits on parent use of intervention strategies and subsequent child language skills is a key step in customizing parent-mediated interventions based on parent characteristics. The long-term positive effect of the proposed research is to improve language outcomes of interventions for children with autism by tailoring parent-mediated interventions that capitalize on parental strengths.