Emotion regulation (ER) has been identified as a transdiagnostic risk factor for psychopathology, making it an ideal target for prevention and treatment. This study explores how parents can nurture the development of child ER. In April 2022, a systematic review was executed focusing on malleable factors in the parental emotion-socialization process during middle childhood. Papers in PubMed, Web of Science and Medline were screened on content-related and methodological criteria. Their methodological quality was assessed. Knowledge was assembled using a summarizing framework encompassing four factors involved in emotion socialization. Fifty papers shed light on modifiable factors at the level of parental meta-emotion philosophy, emotion-related socialization behaviors, the ER skills of parents and the emotional climate of the family. Adaptive socialization appears to be context- and child-specific, thereby taxing parents’ ER skills and their ability to put them into practice flexibly. The four changeable factors in the emotion-socialization process are highly intertwined, resulting in four possible entries for parent-directed interventions. Importantly, time should be devoted to the ER capacities of parents and their ability to attune to the situation and their child. Regarding the latter, replication studies are necessary. Recommendations for clinical interventions are provided.