Laughter serves different functions depending on the social context. Sometimes laughter feels good for producers and listeners, serving as a social reward. Sometimes laughter smooths over social tension, promoting affiliation. And sometimes laughter reprimands or teases the target, establishing dominance. The present study examines whether the acoustic properties of spontaneous laughter reflect the context in which it occurs. Pairs of participants (complete recordings N = 141) watched and discussed humorous videos associated with the social tasks of reward, affiliation, and dominance. The acoustic profiles of the 3,370 laughs extracted from their conversations depended on the social context. Affiliation laughter was shorter, quieter, and muffled, while dominance laughter was more unpleasant (e.g., brighter, less voiced, noisier). The combined acoustic variables discriminated at greater than chance accuracy between the social contexts. This research accounts for some of the acoustic variability of laughter and highlights the functional flexibility of nonverbal signals.