Aims: To evaluate the effects of Guided Music Listening (GML) on masticatory muscles and on the amplitude of wake-time tooth clenching in individuals with higher vs lower frequency of clenching episodes. Methods: The electromyographic (EMG) activity of the right masseter was recorded during three 20-minute music (relaxing, stress/tension, and favorite) tasks and a control no-music task in 10 (mean age ± standard deviation [SD] = 21.4 ± 3.0 years) and 11 (22.6 ± 2.9 years) healthy volunteers with higher (HP) vs lower (LP) frequency of tooth-clenching episodes, respectively. EMG episodes greater than 10% of the maximum voluntary contraction (EMG activity of the masseter during tooth clenching) and below 10% (EMG activity during rest) were analyzed. Nonparametric tests were used to assess between-group and within-group (between-task) differences in primary outcome measures. Results: In both groups, EMG activity during rest was the greatest during the stress/tension task, and it was the lowest during the favorite task in the LP group and the relaxing task in the HP group (all P .001). In the HP group, the amplitude of clenching episodes was significantly lower during the favorite and stress/tension tasks than during the relaxing task (all P .05), while in the LP group, it was significantly lower during the stress/tension task than during the control task (P = .001). The experiment did not affect the frequency or duration of clenching episodes. Conclusion: GML modulates masticatory muscle activity. The response to GML depends on the frequency of clenching and the type of music. Keywords: bruxism, guided music listening, oral behaviors, surface electromyography, temporomandibular joint disorders