Multimodal perception of emotions has been typically examined using displays of a solitary character (e.g. the face-voice and/or body-sound of one actor). We extend investigation to more complex, dyadic point-light displays combined with speech. A motion and voice capture system was used to record twenty actors interacting in couples with happy, angry and neutral emotional expressions. The obtained stimuli were validated in a pilot study and used in the present study to investigate multimodal perception of emotional social interactions. Participants were required to categorize happy and angry expressions displayed visually, auditorily, or using emotionally congruent and incongruent bimodal displays. In a series of cross-validation experiments we found that sound dominated the visual signal in the perception of emotional social interaction. Although participants’ judgments were faster in the bimodal condition, the accuracy of judgments was similar for both bimodal and auditory-only conditions. When participants watched emotionally mismatched bimodal displays, they predominantly oriented their judgments towards the auditory rather than the visual signal. This auditory dominance persisted even when the reliability of auditory signal was decreased with noise, although visual information had some effect on judgments of emotions when it was combined with a noisy auditory signal. Our results suggest that when judging emotions from observed social interaction, we rely primarily on vocal cues from the conversation, rather then visual cues from their body movement.