Photosynthesis is an extremely complicated process that is fundamental to supporting plant growth. It is regulated by multiple internal and external factors. Three factors regulating photosynthesis over which cotton producers can exert some influence are the levels of potassium, nitrogen, and soil moisture. Research has shown that deficient levels of all three depress canopy photosynthesis and yield through the production of a smaller plant with less leaf area to intercept incoming solar radiation. In addition, leaf photosynthesis is impacted by potassium at both the stomatal and non-stomatal level. Nitrogen is a component of both proteins and chlorophyll molecules and as such impacts leaf photosynthesis through effects on dark and light reaction components of photosynthesis. Stomatal factors are the dominant photosynthetic regulating influence when moisture deficit stress is severe, while non-stomatal factors predominate when the moisture deficit stress is mild. A producer can impact yield and profitability for a given field through efficient use and management of these photosynthetic regulatory inputs.