This study was to explore investment return of private teak plantations by financial analysis of data gathered from teak owners. The financial analysis was carried out to estimate NPV at 10% discount rate and IRR by 4 factors of log prices, yields, costs and rotation periods. This study designed teak plantation models with 2x4 meters spacing and cutting rotation at age 15, 22 and 30 years for analysis. We set low and high levels for the yield and cost factors, and used FIO and broker prices for the price factor in order to investigate profitability. In the field survey, the teak logs were mostly sold to brokers at lower price ranging from 1,900 – 11,000 Baht/m3. The broker prices were quite lower than FIO prices in terms of logs over 15- year-old. The results of financial analysis showed all positive NPV value and profitable, and yield and price were critical factors affecting profit of teak plantation investment. The brokers bought teak logs by volume or tree system, the price by tree got lower profits than by volume. Therefore, the private plantation owner must concern how to get high yield and price. The teak plantation should be selected on suitable site to reduce risk of investment. It was recommended that the appropriate rotation should be 20-25 years. However, the MAI was also another factor to be taken in consideration on rotation. If it was continuously increasing, it was suggested that the rotation could be extended.