This chapter outlines the significance of Parent-Child Interaction Therapy (PCIT) in facilitating language growth in young children. PCIT’s first phase of treatment, Child Directed Interaction (CDI), is described in relation to literature from child language disorders. Parent-mediated methods, such as responsiveness, engagement, and directive strategies, are linked to the skills taught in CDI (i.e., PRIDE skills). Authors review scientific evidence for the effectiveness of language facilitation strategies, including their three pilot projects investigating PCIT and language growth for children with autism spectrum disorders (ASD). Factors impacting implementation are considered, such as treatment fidelity and dosage, and clinical applications and potential adaptations of PCIT for ASD are discussed.