The negative-evaluative speech acts of aggressive nature, operating in the Russian pedagogical discourse are studied in this paper. The Kazakhstan secondary schools teachers’ oral speeches in the lessons framework are chosen as the research material. The theoretical foundation of the research is based on the interpretation of pedagogical discourse as an institutional type of discourse, characterized by a number of communicative and pragmatic features, as well as an interpretation of verbal aggression as a specific form of verbal behavior aimed at causing harm to a person, group of people or society. Such pragmatic properties of speech acts of insults and ridicule as illocutionary functions and conditions of realization are considered in detail. Insult differs in personal orientation, in "hacking" of social and ethical taboos, i.e., the awareness of the invalid speech acts. A teacher, performing speech act of insult, is aware of its invalidity, at the same time explaining his/her speech acts by positive motives - the desire to improve and correct inappropriate student’s behavior. The insult is represented in the direct and indirect forms. The ridicule, also realizing the purpose of belittling the dignity of the recipient, is accompanied by the mockery that deepens the negative psychological consequences of this speech act for the student. One type of ridicule is an ironic mockery, based on assigning an object of ridicule the unusual features, properties and actions.