Adolescence is a crisis period of personality development marked by significant physiological and neuropsychological changes that affect the growth and relationships with others. The uneven maturation of the limbic system and prefrontal cortex structures, characteristic of adolescence, provokes a decrease in subjective control and self-regulation, increased impulsivity, and emotional instability. Qualitative and quantitative morphometric changes in the brain of adolescents can cause behavioral problems, impaired control and self-regulation, a sharp change in areas of cognitive interests, the inability to understand themselves and explain their actions. These features are a predictor of the successful socialization of adolescents. Socialization is seen as a process in which the adolescent acquires the skills necessary for his entire existence in society. Psychophysiological changes in his body determine the nature and characteristics of socialization, relationships with others, the nature of actions, and social contacts. An important feature that promotes the adaptive socialization of adolescents is assertiveness. Assertiveness as personal property of behavior primarily involves the development of confidence, determination, perseverance, self-esteem, empathy, communication skills. The formation of assertive behavior significantly increases the adaptation processes of adolescents, normalizes the emotional sphere, has a positive effect on socialization, and sets the vector of social success, self-actualization, and self-realization.