Literature suggests that by developing strong organizational culture and effective leadership, firms can achieve effective business performance. Although this topic has been researched worldwide, little empirical research has been investigated the association between the three concepts. This paper helps to fill this gap in the literature using the association between the leadership, culture and performance using the data collected from national and global firms with several sectors (manufacturing, finance and telecommunication) in Turkey. A survey was carried out on 295 employees who accepted to respond to our questionnaires. According to this aim, we researched/investigated the related literature and after developing a research model and hypotheses, we made numerous analyses. The outcomes of the statistical analyses of this study have demonstrated the effects of culture and leadership over firm performance. The reliability analyses of the scales used in the study have significant results. Research findings through the completion of regression analyses for testing the hypotheses are consistent with literature. In addition to the statistical results, the findings have been conceptually discussed and concluded. Finally implications have presented for future studies.