The United States and Germany are two predominantly monolingual countries with a significant number of multilingual speakers. Previous research on multilingualism in children on the autism spectrum has found no adverse effects on children's language and communication development but often excluded children with complex communication needs or exposure to more than two languages. Employing a multimodal, multidisciplinary understanding of literacy as a social practice, the current study aimed to analyze what literacy activities multilingual families of preschool children on the autism spectrum engaged in. In addition, the current study investigated what factors influenced parents' choices for their home language and literacy environment and to what degree multilingualism was represented in families' home literacy practices. The current study design combined four phases: (1) online survey, (2) follow-up interviews, (3) video recordings of home literacy practices, and (4) video-cue guided secondary interviews. Six primary caregivers of multilingual preschool children on the autism spectrum across the United States and Germany participated in the current study. Results from the four phases showed that participants engaged in multimodal literacy practices primarily guided by child interest. Home language environments were complex, with all participants reporting a non-dominant language as one of their primary household languages, but most children primarily communicated in the societal language. The societal language was reflected in at least some home literacy activities, even if it was not one of the family's languages of interaction. Service providers and future research should use strength-based and family-centered approaches to support multilingual families of preschool children on the autism spectrum. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]