The purpose of this study was to examine associations between interpersonal problem solving and immature defense mechanisms in addition to whether interpersonal problem solving are predictors of immature defense mechanisms. The participants of the study consists of 428 high schools students (184 of the students were females). Interpersonal Problem Solving Inventory and Defense Style Questionnaire were applied. Results of multiple regression analyses indicated that all variables of interpersonal problem solving skills together accounted for 32% of the variance in defense mechanisms. Specifically, significant predictors of immature defense mechanisms levels were lack of self-confidence, negative approach to the problems, constructive problem solving respectively. Generally, the levels of adolescents resort to immature defense mechanisms, lack of self-confidence and negative approach to the problem of the increase, a decrease in constructive problem-solving skills are seen to be effective. The results of the study was discussd within the results of the previous studies.