This paper aims to understand the relationship between aggressivity and burnout among police officers, more precisely, it investigates whether burnout is a predictor of aggressivity among police officers. The study focuses on the relationship between burnout and aggressivity, using regression analysis to identify aggressivity predictors. The Maslach Burnout Inventory was used to measure burnout, while the Aggression Questionnaire was used to measure aggressivity. A cross-sectional study collected data from 274 male police officers (from PSP – Portuguese Police of Public Security) exercising urban patrol tasks in Porto or Lisbon. Low burnout and moderate aggressivity levels were found, with positive significant correlations. Regression analysis reveals that burnout, more than socio-demographic characteristics, predicts 13% to 22% of aggressivity. In particular, feelings of high depersonalisation and low personal accomplishment are the burnout dimensions that most strongly explain anger and aggressivity, whereas emotional exhaustion only explains 4% of verbal aggression. The study highlights the need to develop prevention strategies of stress, aiming to avoid the development of burnout as occupational chronic stress, and decreasing the risk of developing aggressivity among police officers. Despite the wide literature in the area of police officers’ burnout and individual characteristics (e.g. aggressivity proneness as a personality trait), there is limited research on the relationship between burnout and aggressivity. Within democratic societies where excessive use of force by police officers is criticised, aggressivity predicted by burnout reinforces the need to prevent occupational stress that leads to burnout.