A combination of Raman spectroscopy and X-ray diffraction was used to investigate the insertion of ammonia borane in the 5.5 Å diameter pores of the hydrophobic, all-silica zeolite, silicalite-1F in the pressure range up to 4.8 GPa. Insertion and nanoconfinement result in the appearance of new Raman modes, especially in the N–H stretching region and significant changes in the intensities and pressure dependencies of a large number of other modes. Orientational disorder of the −BH3 and −NH3 groups persists to higher pressures in nanoconfined as compared to the bulk ammonia borane. The structure of the recovered sample was determined by single crystal X-ray diffraction. Each pore in the unit cell was found to contain between 2 and 3 molecules of ammonia borane forming single-molecule chains due to the spatial constraints. In situ, high pressure, X-ray powder diffraction indicated that the compressibility of the ammonia borane-silicalite-1F composite is three times lower than that of empty silicalite-1F due to pore filling. These results show that silicalite-1F can be a suitable nanoscaffold for this important chemical hydrogen-storage material.