The present study is motivated to understand the coupled hydro-mechanical behavior of the buffer material as a part of the multi-barrier system in a nuclear waste repository. Compacted unsaturated bentonite is used as a barrier due to its swelling behavior, establishing tightness around canisters containing nuclear waste when it comes in contact with water. Numerous laboratory infiltration tests have been conducted on FEBEX and MX-80 bentonites to examine the evolution of liquid saturation and swelling upon hydration. In the present work, the data obtained from infiltration experiments is used to analyze bentonites’ coupled hydro-mechanical (HM) behavior. Accordingly, a coupled HM model was developed to capture the swelling of bentonite upon its interaction with water in hydration experiments. This HM model uses Richard’s equation to describe the unsaturated fluid flow in the buffer. An elastic constitutive model based on Hooke’s law, augmented by the swelling-induced stress, was adopted to describe the mechanical response in the buffer. The proposed HM model was validated against the measured relative humidity data from experiments for the FEBEX and MX80 bentonites and showed a good agreement. In addition, this modeling strategy effectively captures the variation of the swell pressure of the buffer with changes in saturation upon hydration.