To investigate positive health and its associations with supportive relationships with friends and family members, we conducted an analysis of data from the 2002 Irish Health Behaviour in School-Aged Children Study (HBSC); a cross-sectional survey of 8,424 Irish schoolchildren aged 10-18. 36.0% and 63.4% of the students reported lack of emotional and physical symptoms respectively, 56.1% reported high life satisfaction, 46.9% scored highly on positive life index and 44.2% reported that they are very happy with their life. Parent, sibling and friend relationships were independent predictors of positive health, with higher odds ratios for parents than those for siblings or friends. A greater number of supportive relationships was strongly associated with positive health. Gender and age variations are also reported. The data suggest that there are gains to be made in terms of adolescent health from assisting adolescents to build and maintain their interpersonal relationships, and independently to support parents in their relationships with their children.