This study sought to examine the relationship between corporate governance and organizational efficiency in courier service firms. Data for the study were obtained from 149 courier service companies, randomly selected from the 237 currently operating in that industry sub-sector of Nigeria. The ordinary least square (OLS) regression method was used in testing the degree of relationship between selected corporate governance variables used and organizational efficiency measured by output per staff, cost per service provided and cost per client served. It was found that corporate governance code, board size, internal audit, separation of board chair from CEO and the number of non-executive directors were positively associated with organizational efficiency. These results confirmed a number of findings from earlier studies and also showed that corporate governance is as critical to courier service firms as it is to other companies operating in sectors that provide essential business services. The findings formed the basis for recommending development of internally generated and company-specific code of governance, relatively small board size, and separation of offices of board chair and CEO for courier service firms.