The effective treatment of child conduct problems is understood to rely on a range of therapist competencies, yet these have rarely been an explicit focus of research. In this practitioner review, we examine core competencies for the delivery of evidence-based parenting interventions for conduct problems in early-to-middle childhood. These are examined in light of research into the common elements shared by these interventions, literature regarding common challenges in these interventions, and conceptualisations of such competencies in other fields of mental health. We report on the development of a novel consensus-based model of core competencies for evidence-based practice in this field, based on consultation with an international expert panel. This includes competencies as they apply to complex presentations of conduct problems. Despite considerable variation among widely disseminated programmes in terms of content, format and skills-training practices, there is strong consensus among practitioners regarding core competencies. These relate to three broad domains: (a) generic therapeutic competencies; (b) parenting intervention competencies; (c) specific parenting skills/techniques. Practitioners working with conduct problems, particularly complex presentations thereof, require competencies for engaging not only mothers, but fathers and diverse/non-traditional caregivers and other stakeholders, in evidence-based parenting interventions. Moreover, the successful delivery of these interventions necessitates competencies that extend beyond behaviour management and encompass broader aspects of the family system and the wider ecology of the child.