This paper analyzes results of foreign researches of assertive behavior concerning its connection with the subject’s appeal, his/her locus of control, self-determination and decision-making.It is established that people with high assertiveness make themselves known in a positive vein in comparison with people with low assertiveness; they estimate the level of their own comfort, the benefit to society and importance of assertive behavior higher. Their evaluation of their own appearance significantly influences assertiveness of individuals: if it is high, it improves assertiveness; if it is low, it lowers it.Women’s perception of assertive behavior may differ from men’s perception of assertive behavior. Women with high assertiveness are estimated as less attractive, in comparison with women with average assertiveness; they obtain the lowest estimates from female examinees. Estimates of women’s assertiveness by men who were potential dating partners were positive contrary to inconveniences which women can experience because of their assertive behavior in business and professional situations. Internals behave more assertively than externals, and this interrelation is highly significant for men.The author confirms the connection between self-determination of learners and assertiveness as a whole and with its components: persistence and greater initiative. Statistically significant correlations between assertiveness and quality of life, self- determination, self-efficiency are revealed.Individuals with high assertiveness cope better with recognition of a situation and orientation in a problem, with finding optimal decisions; they are sure that they can find them better than others. Assertive individuals have shown higher motivationto criticism, than not assertive individuals, and highly assertive persons have stated their abilities to criticism and its usefulness more surely. The author has offered a reliable and valid technique of measuring assertiveness.