The article addresses the issue of assertiveness and its relationship with personality factors in teenagers. The research revealed that teenagers with a high level of assertiveness are characterized by a high level of initiation of social contacts and self-confidence, relate better to themselves and others, use a greater number of behavioral strategies in difficult situations. The empirical study also identified statistically significant relationships between certain personality factors and assertiveness. The high level of assertiveness directly correlates with the high level of development of teenager personality traits such as: conscientiousness, extraversion, autonomy, kindness and emotional stability.