This paper examines elements contributing to the effectiveness of firefighting teams carrying out typical tasks. Fourteen firefighter crews were filmed during nineteen real operations and answered questionnaires relating to psychosocial dimensions. Results have shown that “enriched closed-loops” of communication, positive emotional interactions and a “gamma” type of adaptation are positively related to team effectiveness. Conversely, open and incomplete loops of communication, negative emotional interactions, “beta” and “alpha” types of adaptation are negatively related to team effectiveness. Furthermore, there is a mediated link between organisational trust and motivation on the one hand and team effectiveness on the other. These findings highlight the necessity to consider both cognitive and psychosocial variables to account for team effectiveness in the firefighting profession. They also emphasize the need to expand firefighter training to the “non-technical” aspects of the competence.