Studying the hygroscopic behavior of bamboo is important for industrial applications because it influences the dimensional stability and mechanical properties of the final bamboo products. In this study, the water vapor sorption behavior of 14 bamboo species was investigated using a dynamic vapor sorption apparatus and the results were analyzed using the Guggenheim-Anderson-de Boer (GAB) and Hailwood-Horrobin (H-H) models. The different bamboo species exhibited varying sorption isotherms and degrees of hysteresis. The reasons for this may be related to the different sorption isotherms of the two main cell units of bamboo, namely the fiber and parenchyma cells, and the chemical composition of bamboo. The GAB and H-H models provided good fits to the experimental data and meaningful physical parameters regarding the monolayer capacity, especially the water accessible specific surface area can be obtained from the GAB parameters. The fiber saturation point values were also determined using the GAB and H-H models, which ranged from 16.37 to 27.91% for the different bamboo species.