This study examined factors of implementation in clinical practice across the world of the Pediatric Autism Communication Therapy, an evidence-based parent-mediated therapy. Data were gathered via a survey administered to professionals trained in Pediatric Autism Communication Therapy and parents with whom they worked. The study was a mixed-method design informed by the Consolidated Framework for Implementation Research. Over 70% of the practitioners recorded the intent to implement therapy after Pediatric Autism Communication Therapy training. Implementation was more likely if the practitioner saw mostly autistic children within their work (odds ratios [approximately equal] 5), was easier with new referrals, and with peer support from colleagues and managers, allowing scheduling flexibility. The main barriers for practitioners were time (sessions > 1 h), suitable video equipment, low parental self-reflection abilities and family stress. Parents rated the feasibility of learning and using Pediatric Autism Communication Therapy in daily life highly (median = 5.4; interquartile range = 4.5, 6.8; range = 1-7) and delivered home-based practice a median of 4 days per week (daily practice recommended). The facilitators of implementation for parents included positive regard for the features of the Pediatric Autism Communication Therapy method (video reflection, parental empowerment, and play-based practice). The barriers for parents were mostly related to time availability. These results outline the importance of family and system-context factors necessary for successful parent-mediated therapy implementation.