Prior research demonstrates that the discrete emotional displays of leaders, such as anger and happiness, send social information to followers that helps to direct team members’ focus, understanding of the situation, and motivation, boosting team performance. We argue that a key assumption underlying this research is that leaders’ emotions are informative to followers, sending consistent social information. Here, we extend socio-functional approaches to emotion by investigating what happens when the patterns of leader emotional displays are unpredictable to followers. Taking an emotions as social information perspective (van Kleef, 2009), we propose that follower perceptions of leader emotional unpredictability sends social information to team members that there is uncertainty in how the leader allocates resources within the team. This is expected to cause intra-team conflict among followers and to thereby reduce team performance. Using a multi-method approach, we find support for our model in a set of five studies, including a scale-validation study, a field study of 246 retail teams, a laboratory study of interacting groups, a laboratory study with a confederate actor, and an online experiment. The findings inform our understanding of how leaders’ emotional displays influence team performance, extending EASI theory to include how unpredictability in leaders’ expressions of emotions can be dysfunctional for teams.