Background: Parental input plays a central role in typical language acquisition and development. In autism spectrum disorder (ASD), characterized by social communicative and language difficulties, parental input presents an important avenue for investigation as a target for intervention. A rich body of literature has identified which aspects of grammatical complexity and lexical diversity are most associated with child language ability in both typical development and autism. Yet, the majority of these studies are conducted with English-speaking children, thus potentially overlooking nuances in parental input derived from cross-linguistic variation. Aims: To examine the differences in verbal parental input to Bulgarian- and English-speaking children with ASD. To examine whether aspects of verbal parental input found to be concurrent predictors of English-speaking children's expressive language ability are also predictors of the expressive language of Bulgarian-speaking children with ASD. Methods & Procedures: We compared parental input to Bulgarian-speaking (N = 37; 2;7-9;10 years) and English-speaking (N = 37; 1;8-4;9 years) children with ASD matched on expressive language. Parent--child interactions were collected during free play with developmentally appropriate toys. These interactions were transcribed, and key measures of parental input were extracted. Outcomes & Results: English-speaking parents produced more word tokens and word types than Bulgarian-speaking parents. However, Bulgarian parents produced more verbs in relation to nouns and used more statements and exclamations but asked fewer questions than English-speaking parents. In addition, child age and parents' use of questions were significant concurrent predictors of child expressive vocabulary. Conclusions & Implications: This is one of the first studies to conduct a cross-linguistic comparison of parental input in ASD. The differences found emphasize the need to further study parental input to Bulgarian children and adapt naturalistic parent-mediated interventions to the local language and its specific characteristics.