Autosegmental approaches to phonology developed, in part, from attempts to capture the systematic yet apparently complex grammatical tone systems found in many African languages (Goldsmith, 1976; Leben, 1973; Williams, 1976). Since that time, the development of phonological theory has contributed greatly to the understanding of other nonlinear problems that had previously eluded traditional segmental analysis (cf. Goldsmith, 1990). The field of acquisition, however, has been slow to adopt and integrate new perspectives from theoretical phonology. Much work on the acquisition of phonology has utilized a segmental approach based primarily on insights from structural linguistics (Jakobson, 1941/1968) or Chomsky and Halle (968), henceforth SPE (Smith, 1973). Even recent volumes on the acquisition of phonology (e.g., Ferguson, Menn, & Stoel-Gammon, 1992) have focused primarily on segmental issues. This is despite the fact that some early researchers realized the importance of a prosodic approach to acquisition issues (e.g., Kiparsky & Menn, 1977; Spencer, 1986; Waterson, 1971, 1987). In this chapter I pursue an autosegmental analysis of both lexical and grammatical tone, investigating the acquisition of tonal representations, tonal sandhi rules, and the mapping between tonal and segmental tiers in Sesotho, a southern Bantu language.