Even the simplest social interactions require us to gather, integrate, and act upon, multiple streams of information about others and our surroundings. In this Element, we discuss how perceptual processes provide us with an accurate account of action-relevant information in social contexts. We overview contemporary theories and research that explores how: (1) individuals perceive others' mental states and actions, (2) individuals perceive affordances for themselves, others, and the dyad, and (3) how social contexts guide our attention to modulate what we perceive. Finally, we review work on the cognitive mechanisms that make joint action possible and discuss their links to perception.