Conversational involvement refers to the degree to which participants in a communicative exchange are cognitively and behaviorially engaged in the topic, relationship, and/or situation. It is argued that involvement should be viewed from a functional perspective and conceptualized as entailing fiue dimensions: immediacy, expressiveness, interaction management, altercentrism, and social anxiety. Specific nonverbal behaviors that are actually encoded to express involvement along these five dimensions are examined within an interview context. Unacquainted dyads (N=52) engaged in baseline interviews followed by a second interview in which one participant was asked to increase or decrease involvement significantly. Tiuentyone kinesic, proxemic, and vocalic behaviors were rated during five intervals. Change scores from baseline to manipulations shouted numerous differences between high and low involvement, as did correlations between magnitude of involvement and nonverbal behaviors. The behaviors that most strongly discriminated high from low involvement were general kinesic/proxemic attentiveness, forward lean, relaxed laughter, coordinated speech, fewer silences and latencies, and fewer object manipulations. Behaviors most predictive of magnitude of involvement change were facial animation, vocal warmth/interest, deeper pitch, less random movement, and more vocal attentiveness.