The purpose of the study was to empirically explore the effect of effectual entrepreneur set of means in opportunity exploitation capability. Moreover it used number of founders as a moderator variable to examine if the number of founders strengthening or weakening the effect of effectual entrepreneur set of means in opportunity exploitation capability. This study used a cross-sectional survey design which is useful for investigating quantitative description of trends, attitudes, or opinions of a population from a representative sample of the focal population. 300 sample of entrepreneurs in five regions in Tanzania was collected. In this study Structural Equation Modelling(SEM) was used to examine the direct effect of effectual entrepreneur set of means in opportunity exploitation capability. After hypothesis testing, the empirical results indicated the significant and positive relationship between effectual entrepreneur set of means and opportunity exploitation capability. Also the study discovered that the relationship was influenced by the number of founders. These results are useful to all entrepreneurs especially who want to start the new venture. The entrepreneurs where the data were taken are recommended to use this techniques due to the reasons that they work in the environment where they experience uncertainties and unsupportive business environment.