This study compares the phonology of Konso, Diraytata and Mosittachalanguages which belong to the Konsoid subgroup in the Lowland East Cushitic family. Theaim is to identify and describe the phonological similarities and differences that existamong these languages. The classification of the languages’ sound systems, gemination,phonotactics and syllable structures are carried out in order to determine the major patternof differences and similarities. Some major sound changes are discovered and the mergerof voiced obstruents into voiceless counterparts is another major finding observed in theselanguages.