The study focused on the entrepreneurship behaviour: a tool to enhance effectiveness of selected small business owners in Abia State. The specific objectives are to assess the effect of entrepreneurship behaviour on effectiveness of Selected Small business owners in Abia State and analyse the factors mitigating against entrepreneurial behaviour on effectiveness of Selected Small business owners in Abia State. This research adopted a survey design. This study adopted two sources of data collection which are primary data and secondary data. A sampling random sampling method was adopted. Regression model were adopted to establish the effect of dependent and independent variables in the study. The findings of the study stated that Entrepreneurship behaviour has a significant effect on effectiveness of Selected Small business owners in Abia State with p-value = .005 < .05 significant level. Factors mitigating against entrepreneurial behaviour has a significant effect on effectiveness of Selected Small business owners in Abia State with p-value = .009, 001 and .012 respectively < .05 significant level. The study recommended that the entrepreneurs should show more proactive in solving behavioural problems and predicting and preventing future challenges in order for them to achieve business growth that competes in any business environment.