From the very early treatises, Plotinus highlights that the perception of harmonies and rhythms could lead up to the grasp of intelligible harmony. While Plotinus abandons the link between music and astronomy, distinguishing himself from the general reading of Plato developed in the imperial era, he stresses the psychagogical dimension of music. On the one hand, he simplifies the analyses devoted to music as a preparatory discipline, but on the other, he draws upon examples from the arts of rhythm (namely dance and music) to illustrate key aspects of his cosmology and of causal processes. After reviewing the place of music in Plotinus’ metaphysical organization, this chapter examines the use Plotinus makes of images related to music, dance and rhythm to exemplify different causal relationships. It concludes with an analysis of the meaning of a hapax, the adjective arrhythmistos taken from Aristotelian doxography and initially associated with the primordial indetermination of matter. These considerations lead to the conclusion that, in the Enneads, the concept of rhythmos goes beyond the field of musical arts and denotes the dynamic productivity of intelligible realities.