Abstract: While major-third cycles from the nineteenth century are abundant and well studied, they are rare in the eighteenth century and remain poorly understood. Remarkably, we find three major-third cycles in two E♭ major works composed by Mozart in 1788: one in the finale of the Symphony K. 543, and one each in the first movement and the finale of the Divertimento for String Trio, K. 563. In this article, I analyze how Mozart integrates these anomalous equal divisions of the octave into the tonal language of the classical style. In doing so, I further our understanding of eighteenth-century chromatic practice and shine a light on some pitfalls of reductive analysis. Using a combination of Schenkerian and neo-Riemannian tools, I analyze the concrete voice-leading patterns and registral connections Mozart draws out of these abstract structures. I critique existing tendencies to regard these progressions as mere connectors, and caution against premature imposing uninform voice-leading patterns or register on them in analysis. Ultimately, I argue we need to take these oft-neglected parameters into account when assessing how these cycles function in the context of Mozart’s developmental scripts.