Type Ia supernovae (SNe Ia) provide a direct measure of the expansion history of the universe and have led to the discovery of the accelerated expansion, or dark energy. The key goal of observational cosmology for the coming decade is to constrain the nature of dark energy, and SNe Ia remain a vital component. The current state-of-the-art SN Ia experiments are already limited by systematic errors. Shifting observations to the near-infrared (NIR) has been shown to be the most promising way forward. The Carnegie Supernova Project II (CSP II) is a five-year program to obtain optical and NIR observations of 100 SNe Ia located in the Hubble flow. The main emphasis is to obtain NIR light curves and spectra in order to achieve a distance precision of 1-2%, as well as to build a definitive low-redshift reference for future rest-frame NIR observations of SNe Ia at cosmological distances with the next-generation dark energy experiments.