The availability of soil water to crops is considered to be the major limitation to crop production in the U.S. Use of conservation tillage systems enhances soil residue cover, water infiltration and reduces evaporative soil water loss. Our objective was to measure cotton (Gossypium hirsutum L.) leaf level photosynthesis, stomatal conductance, transpiration, and water use efficiency during reproductive growth under different row spacing and tillage conditions on a Norfolk loamy sand (Typic Kandiudults; FAO classification Luxic Ferralsols) in east-central AL. The study used a split-plot design replicated four times with row spacing (standard 40 in row and ultra-narrow row) as main plots and tillage systems (conventional and no-tillage) as subplots. These results indicate that cotton grown with standard row spacing can maintain a higher rate of photosynthesis when soil water was not limiting during the early stages of reproductive growth. At latter stages, no-tillage management may aid in conserving soil water needed during critical reproductive stages such as boll filling when demand for water is high.