Background: Young children with a developmental delay (DD) show significant delays in communication and language development. Although several parent‐implemented language intervention programs have been developed to facilitate the communication and language abilities of children with a DD, no systematic review has examined the effects of these programs. Method: The literature search for this systematic review focused on parent‐implemented early language interventions for children with a DD age 1–5 years. Searches were conducted in PubMed, Scopus, and Web of Science (search period 1974–2015). Level of evidence (levels I and II) as developed by the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) and study effectiveness were evaluated. Seven intervention studies met the inclusion criteria. Interventions comprised the Hanen Parent Program, Responsive Education/Prelinguistic Milieu Teaching, and Enhanced Milieu Teaching. A substantial proportion of children with a DD also had a diagnosis of Down syndrome (DS). Results: Five of the seven studies reported a significant effect of intervention on parent responsiveness, child communication, and aspects of language interactions (favoring intervention groups over control groups), but no studies reported significant effects of intervention on expressive language vocabulary. Conclusions: Intervention programs aimed at facilitating the communication and language development of children with a DD appear to improve a child's general communication abilities but have limited impact on expressive language development.