The growth of large and well ordered protein crystals remains the major obstacle in protein structure determination by means of X-ray crystallography. One of the reasons is that the physico-chemical aspect of protein crystallization process is not understood. This article reviews efforts towards formulation of models that could become theoretical frameworks for the interpretation of voluminous experimental data collected on protein crystal growth. Special attention is devoted to microscopic models that recognize the role of the shape of protein molecules in crystal formation.