|Abstract:||This paper describes the tone system of the Mamainde language from an OT perspective. Sections dealing with stress and intonation show how these differ from tone. It is pointed out, however, that stress and tone in this language are both based upon the mora and the notion of syllable weight. This analysis has been able to improve on previous studies by reducing the tone system to just a H and L, without resorting to contour tones. The bulk of the paper deals with an interesting tone sandhi evident on some Mamainde verbs, where specific HLH sequences are realized as HHH (also known as plateauing). The *Trough constraint is employed, which restricts HLH sequences in certain situations from being present in the output. The most interesting feature of this tone system is the need for tonal constraints to reference morphology in unique ways, showing a strong connection between morphology and prosody in this language. Specifically, a positional faithfulness constraint is required which applies to tones internal to the stem as opposed to tones which are peripheral. The Mamainde data appears to offer some unique challenges to the current understanding of positional constraints, particularly in regards to the non-peripherality issue. Pitch graphs and tableaus are used throughout.