Background: Metacognition is a significant component of complex interventions for children who have developmental language disorders. Research into how metacognition operates in the content or process of developmental language therapy delivery is limited. Identification and description of proposed active therapy components, such as metacognition, may contribute to our understanding of how to deliver complex communication interventions in an optimal manner. Aims: To analyse aspects of metacognition during therapy derived from a manualized speech and language intervention (the Social Communication Intervention Programme--SCIP) as delivered to children who have social (pragmatic) communication disorder (SPCD) and to examine the dynamic process of delivering therapy. Methods & Procedures: A purposive sample of eight filmed therapy sessions was selected from the video data corpus of intervention-arm participants within a randomized controlled trial. The child-therapist interactions during therapy sessions from five children (aged between 5;11 and 10;3) in the SCIP trial were transcribed. Filmed sessions represented a variety of communication profiles and SCIP therapy content. Starting from existing theory on metacognition, cycles of iterative analysis were performed using a mixed inductive-deductive qualitative analysis. A preliminary list of metacognitive content embedded in the intervention was developed into a metacognitive coding framework (MCF). A thematic analysis of the identified metacognitive content of the intervention was then carried out across the whole sample. Outcomes & Results: Thematic analysis revealed the presence of metacognition in the content and delivery of SCIP intervention. Four main themes of metacognitive person, task and strategy knowledge, and monitoring/control were identified. Metacognition was a feature of how children's ability to monitor language, pragmatic and social interaction skills, in themselves and other people, was developed. Task design and delivery methods were found to play a particular role in adjusting the metacognitive content of the therapy activities. Conclusions & Implications: This study makes explicit the metacognitive content and delivery within a complex developmental communication intervention. Discussion of the findings about metacognitive content provides an explanation of how the skilled speech and language therapist manipulates task demands, person knowledge and therapy methods towards the therapy goal. Clinical applications of the metacognitive framework are discussed. We suggest that the process of making the tacit knowledge of the therapist explicit can contribute to the implementation of complex evidence-based interventions.