The purpose of this study is to find out multi-program high school students' social self-efficacy expectation and assertiveness levels. The results were compared according to gender, kind of high school program, grades, participation to activities, having a sport licence and family income level. A total of 618 multi-program high school students participated to the research. Social Self-Efficacy Expectation Scale and Rathus Assertiveness Inventory were used. The significant differences were identified between the participants' social self-efficacy expectation scores according to gender, grades, participation to activities and having a sport licence. No statistically significant differences were found between the mentioned variables and the participants' assertiveness scores. Moreover, positive relationships were established between family total income and assertiveness scores and social self-efficacy expectation scores.