Background <p>Maternal depression during pregnancy has been associated with increased risk of offspring autism spectrum disorder (ASD) – a highly heritable neurodevelopmental disorder. However, no study to date has taken into account maternal ASD traits in the association between maternal prenatal depression and child ASD.</p> Methods <p>This study utilized data from the Environmental Influences on Child Health Outcomes (ECHO) consortium—a large, national prospective longitudinal study—to examine&#xa0;maternal ASD traits as a covariate and moderator in the association between maternal prenatal depression and child ASD traits. Participants were 645 mother–child dyads. Mothers self-reported prenatal depressive symptoms and ASD traits. Child ASD traits were rated by parents using the Social Responsiveness Scale and Child Behavior Checklist. Maternal depression and child ASD diagnoses were either parent-reported or from medical record review.</p> Results <p>We found that both maternal prenatal depressive symptoms and depression diagnoses predicted child ASD traits (β’s &gt; .04, <i>p</i>’s &lt; .003). These associations remained significant after accounting for maternal ASD traits for the CBCL only (β’s &gt; .42, <i>p</i>’s &lt; .001). Maternal prenatal depression did not predict child ASD diagnoses. Maternal ASD traits predicted child ASD traits and diagnoses (β’s &gt; .06, <i>p</i>’s &lt; .001). Maternal ASD traits did not moderate the association between maternal prenatal depression and child ASD traits.</p> Conclusion <p>Providers might consider early screening for ASD in children of mothers with a history of elevated depressive symptoms during pregnancy.</p>