This paper documents a restriction against the co-occurrence of homorganic consonants in the root morphemes of Muna, a western Austronesian language, and compares the Muna pattern with the much-studied similar pattern in Arabic. As in Arabic, the restriction applies gradiently: its force depends on the place of articulation of the consonants involved, and on whether the homorganic consonants are similar in terms of other features. Muna differs from Arabic in the relative strengths of these other features in affecting co-occurrence rates of homorganic consonants. Along with the descriptions of these patterns, this paper presents phonological analyses of the Muna and Arabic patterns in terms of weighted constraints, as in Harmonic Grammar. This account uses a gradual learning algorithm that acquires weights that reflect the relative frequency of different sequence types in the two languages. The resulting grammars assign the sequences acceptability scores that correlate with a measure of their attestedness in the lexicon. This application of Harmonic Grammar illustrates its ability to capture both gradient and categorical patterns.