It is of clinical relevance to identify possible parental and family factors linked to adolescent problematic gaming (APG). This thesis contains two parts. In the first part I undertook two systematic literature reviews in an effort to identify these factors. In the second part I undertook a randomised controlled trail (RCT) to test the effectiveness of family therapy in treating APG. Results of part 1: parental strategies directly addressing screen use - also called parental mediation techniques - seem to be less effective than general parenting approaches fostering warm and close relationships between the adolescent and the parents. Results of part 2: the family therapy approaches tested within this RCT both had a positive impact on Internet gaming disorder symptoms and overall well-being; the evidence-based approach (multidimensional family therapy) outperforming the family therapy approach as practiced locally. Targeting parental and family factors are a promising therapeutic avenue to treating APG.