We review two fundamentally different ways that decision time is related to cooperation. First, studies have experimentally manipulated decision time to understand how cooperation is related to the use of intuition versus deliberation. Current evidence supports the claim that time pressure (and, more generally, intuition) favors cooperation. Second, correlational studies reveal that self-paced decision times are primarily related to decision conflict, not the use of intuition or deliberation. As a result, extreme cooperation decisions occur more quickly than intermediate decisions, and the relative speed of highly cooperative versus non-cooperative decisions depends on details of the design and participant pool. Finally, we discuss interpersonal consequences of decision time: people are judged based on how quickly they cooperate, and decision time is used as a cue to predict cooperation.