Two studies were conducted to test for the existence of several postulated kinds of assertiveness and to develop a set of scales capable of measuring these hypothesized constructs reliably. The preliminary form of 80 statements was administered to a sample of 175 subjects. A factor analysis confirmed the presence of four dimensions. The item sets were revised, extended and administered to a sample of 304 subjects consisting of 138 men and 166 women. The item correlations were analyzed by the method of principal components and an oblique rotation revealed four correlated dimensions. Items best representing each factor were summed and correlated with measures of Tolerance vs. Hostility, Level of Self Esteem, and Social Desirability. The results indicate that there are four kinds of assertive behaviors: Directiveness, Social Assertiveness, Defense of One's Interests, and Independence. These are relatively independent of hostility and social desirability but are positively correlated with self esteem.