Abstract - Vowel assimilation is a common phonological process in Yorùbá language and its numerous dialects. However, the occurrence of this process differs in the language and its dialects. It is against this backdrop that this study investigates vowel assimilation in Èkìti dialects of Yorùbá. The paper, which is basically descriptive, makes a careful comparison of the phonological process in the dialects and Standard Yorùbá language. The paper shows that unlike Standard Yorùbá, vowel assimilation is confined to certain constructions in Èkìtì dialects. The paper also posits that unlike Standard Yorùbá which employs two assimilation rules, Èkìtì dialects employ one assimilation rule. The rule is however, blocked when there need to maintain contrast