Knowledge and understanding of evapotranspiration (ET) are crucial for a variety of water and energy balance applications. In the past decades, multiple ground observations and models have been used to evaluate the movement of water into atmosphere from different land cover types, while they cannot be conveniently implemented globally due to the former ones' limited spatial coverage and the later ones' complexity. In this study, we further examine the sensitivity of a newly developed remote sensing index, Normalized Difference Latent Heat Index (NDLI), on the potential ET against the other existing indexes in the literature. Results confirm that the newly developed multi-band NDLI exhibits the highest correlation with ET derived from the Surface Energy Balance Algorithm for Land (SEBAL) model as compared to the other indexes. The correlation coefficients are approximately 0.70 and 0.71 for the eastern part of Chiayi City, Taiwan and Thai Binh Province, Viet Nam, respectively.