The study aims to investigate factors effecting leadership style and leadership effectiveness in Small Business at Thanh Hoa Province, Vietnam. Results showed that traits had a positive effect on leadership styles and Skills had a positive effect on leadership styles. Results also showed there was a positive relationship between leadership style and effective leadership. This study couldn’t find any difference in gender, education, experience, position and effective leadership. Thus there was only difference in age and effective leadership for small company in Thanh Hoa, Vietnam. The implication and limitation are also discussed in this research.