Musical sounds and the body are interdependently linked in music performance. The key to musical expression lies in the way the body conducts music over time. In this study, General Tau Theory (Lee, 2005) was used as a theoretical framework to explore the head movements made by a classical guitarist during two performances. The musician’s head movements were analysed in conjunction with sound intensity and temporal features of the music. Differences in expression between the performances were established by listeners’ ratings of audio recordings. Tau-G guided head movements were not found to be related to intensity glides of individual notes, and the tau-coupling constant (k) did not vary between expressively different performances. Significant differences between the two performances in tau-guided head movement timing and musical tempo characteristics suggest that the body’s role in musical expression lies in expressive timing. However, limitations in this study prevent firm conclusions being drawn from these results. Ways of eliminating these defects are discussed and future directions for the application of Tau Theory to body movement in music are identified.