Recent evidence suggests the link between caregiver psychological distress and offspring social-emotional difficulties may be accounted for by offspring temperament characteristics. However, existing studies have only focused on neurotypical children; thus, the current study sought to provide an initial examination of this process among children with varying levels of early autism features. Participants included 103 infants aged 9–16 months (M = 12.39, SD = 1.97; 68% male) and their primary caregiver (96% mothers) referred to a larger study by community healthcare professionals. We utilized caregiver-reported measures of psychological distress (Depression Anxiety Stress Scales), infant temperament (Infant Behavior Questionnaire-Revised) and internalizing and externalizing symptoms (Infant-Toddler Social and Emotional Assessment) and administered the Autism Observation Schedule for Infants (AOSI) at an assessment visit to quantify autism features. Infant negative affectivity was found to mediate positive concurrent relations between caregiver psychological distress and infant internalizing and externalizing symptoms, irrespective of the infants' AOSI score. While preliminary and cross-sectional, these results replicate and extend previous findings suggesting that the pathway from caregiver psychological distress to negative affectivity to social-emotional difficulties might also be apparent among infants with varying levels of autism features. More rigorous tests of causal effects await future longitudinal investigation. Lay Summary: Offspring of caregivers experiencing psychological distress (i.e., symptoms of depression, anxiety, and/or stress) may themselves be at increased risk of poor mental health outcomes. Several previous studies conducted with neurotypical children suggest that this link from caregiver-to-child may be facilitated by children's temperament qualities. This study was a preliminary cross-sectional exploration of these relationships in infants with features of autism. We found that infants' elevated negative emotions were involved in the relation between caregiver heightened psychological distress and children's mental health difficulties, consistent with neurotypical development.