The present review sought to clarify and synthesise the existing research of the role parental harshness and parental warmth have on children and adolescents with callous unemotional traits by comparing research across different study designs and study samples in a systematic review. The systematic review search rendered in 16 publications which revealed that callous unemotional traits moderate the relationship between parental harshness as well as parental warmth and behaviour problems in children and adolescents. The moderation effect was directed by the level of callous unemotional trait in the child or adolescent where those with low levels exhibited the most negative effects when exposed to parental harshness. Conversely, children or adolescents with elevated levels exhibited the most positive effects when being exposed to parental warmth. Furthermore, the review revealed that both forms of parenting predict changes in callous unemotional traits over time, where parental harshness increased traits and parental warmth decreased traits. These results are further discussed in relation to the contextual theories of Lykken’s parental competence and socialisation model as well as Kochanska’s conceptual model of conscience development.