Individuals’ opportunities for action in threatening social contexts largely depend on their social power. While powerful individuals can afford to confront aggressors and dangers, powerless individuals need others’ support and better avoid direct challenges. Here, we investigated if adopting expansive or constrictive postures, which function as social signals of power, impacts individuals’ approach and avoidance decisions in response to social threat signals using a within-subject design. Overall, participants more often chose to avoid rather than to approach angry individuals, but showed no clear approach or avoidance preference for fearful individuals. Crucially, constrictive posture considerably increased the tendency to avoid angry individuals, whereas expansive postures induced no substantial changes. This suggests that adopting power-related postures can impact action decisions in response to social threat signals. The present results emphasize the social function of power postures and are discussed in the context of the debate on the replicability of power posture effects.