BACKGROUND: Surgical excellence demands teamwork. Poor team behaviors negatively affect team performance and are associated with adverse events and worse outcomes. Interventions to improve surgical teamwork focusing on frontline team members' nontechnical skills have proliferated but shown mixed results. Literature on teamwork in organizations suggests that team behaviors are also contingent on psychosocial, cultural, and organizational factors. This study examined factors influencing surgical team behaviors to inform more contextually sensitive and effective approaches to optimizing surgical teamwork. METHODS: This qualitative study of cardiac surgical teams in a large United States teaching hospital included 34 semistructured interviews. Thematic network analysis was used to examine perceptions of ideal teamwork and factors influencing team behaviors in the operating room. RESULTS: Perceptions of ideal teamwork were largely shared, but team members held discrepant views of which team and leadership behaviors enhanced or undermined teamwork. Other factors affecting team behaviors were related to the local organizational culture, including management of staff behavior, variable case demands, and team members' technical competence, and fitness of organizational structures and processes to support teamwork. These factors affected perceptions of what constituted optimal interpersonal and team behaviors in the operating room. CONCLUSIONS: Team behaviors are contextually contingent and organizationally determined, and beliefs about optimal behaviors are not necessarily shared. Interventions to optimize surgical teamwork require establishing consensus regarding best practice, ability to adapt as circumstances require, and organizational commitment to addressing contextual factors that affect teams.