This paper studied the differences and similarities in the lexicon of Standard Yoruba, Ìkàrẹ́ Àkókó and Àkúrẹ́ dialects. We examined the lexicostatistics comparison of the lexicons in Standard Yorùbá, Ìkàrẹ́ Àkókó and Àkúrẹ́ dialects. The paper aims at determining the level of mutual intelligibility in Standard Yorùbá, Ìkàrẹ́ Àkókó and Àkúrẹ́ speech forms. The objectives of this study were: (i) to find out the areas of similarities and differences of the lexical items of the dialects, (ii) to examine the phonological relatedness of the three dialects and (iii) to determine the cognate percentage of relatedness among the three dialects. The data for this paper were collected from six native speakers using the SIL Comparative African Wordlist of basic lexical items. The numeral system, animal nouns and edible nouns were selected from the wordlist in which they were compared using the comparative method and a lexicostatistics analysis was done. The comparative method and the lexicostatistics analysis were used as the framework for Standard Yorùbá, Ìkàrẹ́ Àkókó and Àkúrẹ́ dialects to determine the level of lexical correspondence among them. The findings of this study revealed that there is a higher cognate percentage between Standard Yorùbá and Àkúrẹ́ with 86.40% cognates, with Ìkàrẹ́ Àkókó and Àkúrẹ́ having 74.60% cognates and Standard Yorùbá and Ìkàrẹ́ Àkókó with 78.90% cognates. This paper concluded that there is a higher level of mutual intelligibility between Standard Yorùbá and Àkúrẹ́ than Standard Yorùbá and Ìkàrẹ́ Àkókó while the level of mutual intelligibility between Ìkàrẹ́ Àkókó and Àkúrẹ́ is low.