The study of the effect of Top Management Team (TMT) diversity on organization performance produces mixed results. This study investigated the effect of involvement culture on the relationship between TMT diversity and organization performance. The target respondents were the Heads of Human Resources in all the commercial banks in Kenya and out of the 43 targeted banks, 33 responded. The questionnaire was the maintool of data collection and the data was analyzed using regression analyses. Past studies have shown that the question as to whether diversity leads to organization performance depends of the performance measures used. Since past studies have shown mixed results on the effect of TMT diversity on organization performance, the study usedinvolvement culture as a moderating variable and found that it had a significant effect on the relationship between TMT diversity and organization performance. As a result, since most organizations have diversity at the TMT, they need to make deliberate efforts and invest in good management practices which enhance organization performance. Future studies can find out which other moderating variables have apositive effect on the relationship between TMT diversity and organizationperformance.Key Words: Top Management Team (TMT) Diversity, Involvement culture, Organization Performanc
