Social dilemmas typically require individuals to choose between a personal need and that of a group, often sacrificing one for the other. Many factors play a role in whether people choose to cooperate or to compete, but time constraint and other time-related variables might be decisive in this decision-making process. This study investigated the role of these time variables in individuals’ choice to cooperate or compete, specifically by evaluating time pressure and the individuals’ worldview of time (i.e. how they perceive and think about their present and future). Participants (n = 220) took part in 10 rounds of a social dilemma task (the chicken game), either in a condition with time pressure or a control condition. Participants also completed the Zimbardo Time Perspective Inventory, and the Cooperative-Competitive Orientation Scale. As expected, rates of competition were higher in the experimental condition, where a 40-second timer was set after the fifth round of the dilemma. In fact, more competitive behavior was observed with each successive round in the time-pressure condition, with the last round consistently being the most competitive. Present and future components of the time perspective variable were positively correlated with competitive behavior, but only when under time pressure. No effect was found using the cooperation and competition attitudes measure. These results suggest that time pressure increases competitive behaviors, and that time perspective is related to competition only when there is an explicit time constraint in the decision process.