The aim of this study is to analyze the relationships between leadership effectiveness, knowledge sharing behavior, business performance, firm strategy, and firm performance. In this study, to reveal the relationships, statistical analyses were applied to the data collected using one-to-one questionnaire techniques while the relationships between the variables were tried to be revealed. In this study, the importance of knowledge sharing behavior and the positive effects of both independent variable and mediator variable on the organization are emphasized. In addition, the positive effect of leadership effectiveness and knowledge sharing behavior on work performance, firm strategy, and firm performance variables was detected. Analysis was made using LISREL, IBM SPSS 23 software program, and SPSS PROCESS V.3 add-in, and confirmatory and explanatory factor analysis and reliability analysis were performed on questions using Likert-type scale. In the analysis of the relationships between variables in the correlation menu of the main menus of SPSS Program, the regression menu was used to test the hypotheses and to reveal the mediation variable effect of the PROCESS V.3 add-in. Confirmatory factor analysis was performed by LISREL program.