Both naturalistic developmental behavioral interventions (NDBIs) and augmentative and alternative communication (AAC) have been shown to support the language development of children with a diagnosis of autism spectrum disorder and minimal speech. However, little research has addressed the impact of incorporating AAC systems within NDBIs. This systematic review was conducted to assess the relative impact of NDBI procedures "with" and "without" AAC on the language development of children on the autism spectrum with minimal speech. Relevant studies were located through systematic database searching, targeted review of relevant journals, and ancestral search of references from identified and associated papers. Relevant study characteristics were coded for all included studies, as well as determining certainty of evidence and calculating effect sizes for language variables. All procedures followed the systematic review guidelines set by the Cochrane Collaboration. A total of 29 relevant studies were included within this review, covering both single-case and group design research. Three studies were identified that directly compared NDBI and AAC interventions. NDBIs had a strong impact on language across study types (i.e., with and without AAC), though both aggregate and comparative effect sizes were notably larger when AAC was included within NDBI procedures, as compared to NDBIs without AAC. Results suggest that combining AAC with NDBI procedures may lead to better language outcomes than NDBIs alone for children on the autism spectrum with minimal speech.