This thesis examines parent-mediated interventions for children at risk for and diagnosed with autism spectrum disorder (ASD) across three papers. The first paper is a narrative literature review, evaluating parent-mediated early interventions (PMEI) for children up to the age of three years in terms of behaviours related to synchrony. The review identifies specific parent and child behaviours that are targets in diverse interventions. It integrates quantitative and qualitative evidence, and summarises evidence suggesting that PMEIs increase synchrony in parent-child dyads with children at risk for and children diagnosed with ASD. The second paper is a qualitative empirical study, examining parents’ experiences of participating in a parent-mediated intervention, using an interpretative phenomenological analysis (IPA) methodology. Seven mothers and one father of children with socialcommunication impairments were interviewed using semi-structured interviews. Four interrelated themes were identified: The Parent-Child Relationship theme described parents’ experience of relational and affective changes in the parent-child relationship over time. The impact of experiencing specific aspects of the process of participating in PACT emerged as the theme Expectations and Processes. Parents’ described participating in PACT evoked significant negative feelings as a result of knowledge gained through PACT (Heartbreak, Failure, and Guilt). Growth of Understanding captured parents’ experience of learning and a sense of empowerment. By taking a qualitative approach this study focused on the process issues rather than the outcomes of the intervention. The third paper integrates findings from the literature review and the empirical study, and discusses implications for theory, future research and clinical practice. This paper also includes personal reflections on the research process.