Coronal harmony in Dholuo refers to the co- occurrence restriction on dental and alveolar obstruents and nasals. The purpose of this paper is to describe and explain coronal harmony as it manifests in Dholuo. This involves an examination of the phonetic and phonological properties that define coronal harmony in Dholuo. In an Optimality Theory account of coronal harmony in Dholuo, the paper adapts Rose and Walker (2004) surface correspondence constraints CORR-T↔T which demands identity in all respects between segments and CORR- T↔D where voicing may be different but manner and place of articulation must be identical if at all harmony is to be achieved. The phonological feature distributed [dist] is the distinctive feature amongst the coronals. The paper also proposes that some of the morphophonemic alternations attested in Dholuo grammar are motivated by consonant harmony phenomenon