Aim of this research is to examine the relationship between adolescents' subjective well-being and parenting style and smartphone addiction by several variables. The research population was composed of high school students studying in Kocaeli province in the academic year of 2017-2018. The sample was composed of 671 adolescents attending 6 different high schools which were randomly chosen out of this population. 313 (46.6%) of the participants are female, 358 (53.4%) of them are male. Relational survey model was used in the research. Data were collected using Personal Information Form, Smartphone Addiction Scale, Adolescent Subjective Well-Being Scale and Parenting Style Inventory. It was found in the research that participants' smartphone addiction levels did not differ statistically and significantly by gender, whether parents were together or divorced, and parental income. A negative significant relationship was found between academic achievement and smartphone addiction. According to the analysis results, as the smartphone usage duration extended, smartphone addiction level increased. The results of the analysis conducted to determine whether smartphone addiction was predicted by adolescents' subjective well-beings and the parenting styles (acceptance/involvement, psychological autonomy and strictness/supervision) showed that all variables other than parental acceptance were negative significant predictors of smartphone addiction. It was concluded that subjective well-being was the most important predictor of smartphone addiction.