In this paper we have made strong distinction between managerial and entrepreneurial orientations of leadership and argued that these orientations should have different effects on the performance of companies. Data were collected from a sample of 204 owner-managers of Sri Lankan companies by administering a mailed paper questionnaire. Company performance was measured by the ratings of sales performance on the part of managers concerned. Correlation and regression analysis were then performed in the impact analysis. Our findings indicate that the leadership orientation of owner-managers of small firms is more entrepreneurial than managerial. Also, entrepreneurial orientation (EO) correlated more significantly with firms’ performance than did managerial orientation (MO), and the relative impact of mixed orientations of leadership on company performance is more positive than that of MO in the case of medium and large firms. This paper advances the theoretical work into leadership and entrepreneurship and adds to the body of knowledge in the context of developing countries. Practical implications for the research include assisting owner-managers to determine the likelihood of appropriate leadership orientations relevant to their particular context and firm size.