The present state of some key aspects of development of concrete plasticity is summarized. Emphasis is placed on the representation and interpretation of the inelastic deformation of concrete materials in the post-elastic range. The development of plasticity-based models in prepeak stress range is first summarized, emphasizing the fundamental concepts peculiar to concrete materials. A general formulation of softening behavior by the plasticity theory combined with the fracturing (damage) theory is then discussed. Next, recent studies relating macrospace features and microscopic events are presented. Finally, the role of cement-paste-sand interfaces in providing a deeper understanding of the concrete materials at the microscale are explored. Directions for further research are indicated.