Current strategies for boosting rice productivity encounter diminishing returns as rice crops approach yield ceilings. This chapter describes how improvement of photosynthetic efficiency is needed to boost yield ceilings. This can be in the context of C3 photosynthesis, overcoming single limitations and maintaining optimal distribution of resources within the photosynthetic apparatus. The chapter shows that chloroplast-specific photorespiratory bypasses can lead to improvements in overcoming photorespiration-related limitations. The most significant enhancement would be engineering the C4 photosynthetic pathway into rice. The chapter argues that a major priority in the early phase of C4 engineering is targeting genes responsible for C4 structure and function.