Recent spectroscopic investigations of various amino acids report intriguing high‐pressure and low‐temperature behavior of NH3+ groups and their influence on various hydrogen bonds in the system. In particular, the variation of the intensity of NH3+ torsional mode at different temperatures and pressures has received much attention. We report here the first in situ Raman investigations of fully deuterated α‐glycine up to ∼20 GPa. The discontinuous changes in COO− and ND3+ modes across ∼3 GPa indicate subtle structural rearrangements in fully deuterated α‐glycine. The decrease in the intensity of ND3+ torsional mode is found to be similar to that of undeuterated α‐glycine. The pressure‐induced stiffening of ND and CD2 stretching modes are discussed in the context of changes in the hydrogen‐bonding interactions. Copyright © 2011 John Wiley & Sons, Ltd.