Background: The aim of many interventions used by speech and language therapists (SLTs) is to change behaviours related to communication and interaction. Parent-led language interventions for children in the early years (0-5 years) rely on SLTs supporting parents to change their behaviour in child-focused interactions to effect a change in the child's communication. Therapeutic techniques used by SLTs in parent-led language interventions are largely underspecified, impacting on intervention reporting, replication, trialling and development. The Behaviour Change Technique Taxonomy Version 1 (BCTTv1) offers a method of describing intervention techniques developed for use in public health interventions, but with several examples of its application to speech and language interventions. Aims: To identify behaviour change techniques (BCTs) from the BCTTv1 occurring in parent-led language interventions for children in the early years. Methods & Procedures: A literature search identified relevant descriptions of parent-led language interventions. These were coded using the BCTTv1. A reliability check was carried out on 10% of the descriptions. To confirm the use of identified BCTs in clinical practice, results of the literature search were triangulated with an online survey of SLTs, and observations of SLTs delivering parent-led language intervention. Outcomes & Results: A total of 84 papers containing descriptions of 45 interventions were coded; 62 SLTs responded to the survey and three SLTs were observed delivering parent-led language intervention. A total of 24 BCTs were identified in the literature search, replicated in the observations and verified by SLTs in the survey. BCTs were identified at two levels: Level 1 SLT implemented to change parent interactive behaviour; and Level 2 parent implemented to change child communicative behaviour. Conclusions & Implications: The BCTTv1 is a useful starting place for describing parent-led language interventions. With some additions and adjustments, BCTs identified in this study were immediately recognized by practitioners and can easily be adopted into practice.