The subject of this paper is a comparative analysis of aggressiveness and assertiveness in communication with the objective to reveal some fundamental shortcomings of the popular theory of assertivity, i. e: insufficient thematization and articulation of ethical and social issues; excessive emphasis on behavioral (manifest) components of communication, at the expense of its motivational and intentional aspects; overestimation and idealization of the effects of assertive techniques and philosophy due to the neglect of real social relations marked by asymmetry of power. Verbal aggression is defined as a communication act by which one, intentionally or unintentionally, consciously or unconsciously, hurts the other person via language. Assertiveness means the willingness of people to confirm or protect their rights and express their feelings in a socially appropriate way. The criteria of 'social appropriateness', however, do not guarantee ethics and truthfulness of communication, or their protection from aggression. The establishment of assertiveness on subjective feelings and perceptions of one's own and others' rights deprives them of a more objective and rational ground of legitimacy. The way in which the assertiveness theory is presented and promoted eliminates the necessary contrasts and tensions between descriptive ('is') and normative ('should be') levels. In order to fulfill its humanistic purpose and to be a responsible method of communication, in other words, to avoid serving as a socially accepted cover for aggressiveness, it has to meet a lot of other requirements that go beyond the sphere of behavioral and communication skills.