<p>This special issue on the affiliative dimension of nonverbal behavior brings together cutting-edge thematically-linked empirical research examining how nonverbal cues signal, reflect, and shape affiliation and social connection. The contributions clarify the causal direction of the relationship between nonverbal cues and affiliation—whether behaviors such as laughter, mimicry, and synchrony create social closeness or emerge from it. Collectively, the papers also refine theoretical distinctions among affiliative signals by disentangling the overlapping and unique functions of backchannels, nodding, and laughter. Finally, this issue highlights the growing importance and utility of automated methods, such as the use of AI-generated avatars and motion capture technology, which allow for greater precision in isolating and measuring cues within dyadic interaction. Together, these studies advance a more nuanced and methodologically sophisticated understanding of how affiliation is expressed through our nonverbal behavior.</p>