The purpose of this study is to examine the effect of the quality of internal auditors on the financial performance of the selected small and medium enterprises in South-west, Nigeria. This was executed by selecting Ogun, Ondo, and Osun states of the South-west region of Nigeria as case studies. Using a survey design, data were collected from 299 SMEs across the selected region. The descriptive results indicate that respondents perceive the quality of internal audit to be relatively high across SMEs in South-west Nigeria. The study recommends that business owners should improve the effectiveness of internal auditing to strengthen their decision-making capability and ensure accurate, error- and bias-free financial reporting.