Vegetation phenology is sensitive to climate variability, and understanding changes in phenology are necessary to infer the response of forest towards climatic variability. In this study, time series of Normalized Difference Vegetation Index (NDVI) extracted from Moderate Resolution Imaging Spectroradiometer (MODIS) from 2009 to 2012 was used to investigate changes of teak plantation phenology in Lampang Province. The NDVI was validated by Leaf Area Index (LAI) and the negative logarithm of the ratio of daily downward solar radiation on the forest floor to that above the canopy (NLR). The results show that NDVI was significantly correlated with LAI (r=0.81), and NLR (r=0.77). Analysis from phenology metrics shows that length of growing season ranged between 264-324 days, starting from March to May and ending in January to March of the following year. In 2010, the starting of this growing season was delayed and the length of season was shorter than other years. NDVI was negatively correlated to maximum temperature (r=-0.85, p This study demonstrates that NDVI extracted from satellite is able to capture the teak plantation phenology and provide spatial and temporal information for long term monitoring. The significant correlation between NDVI and climate factors in this study implies that future variability in meteorological variables under climate change would affect the forest ecosystem.