Communication episodes may range from highly interactive to noninteractive. The principle of interactivity refers to the constellation of structural and experiential features associated with interactivity that systematically affect communication processes and outcomes. One such feature is degree of participation. In deceptive interchanges, senders may engage in dialogic (high participation, two-way) or monologic (low participation, one-way) communication. According to the principle of interactivity, dialogue should advantage deceivers relative to monologue due to increased mutuality between sender and receiver and greater opportunities for deceivers to improve their performance over time. An experiment in which friends or strangers alternated between deceiving and telling the truth to a partner under dialogue or monologue conditions tested this principle. All hypotheses received some support. Relative to monologue, dialogue created more mutuality among strangers. Dialogue also enabled deceivers to better manage their informational content, speech fluency, nonverbal demeanor, and image, resulting in less accurate deception detection by partners. These results support the interactivity principle and interpersonal deception theory, from which the principle emanated.