Development of modern water and wind erosion prediction technology requires information on the canopy structure of various plant species to accurately predict the canopy effect on the falling raindrop or the erosive force of the wind. The objective of this study was to develop equations to predict grain sorghum [Sorghum bicolor (L.) Moench] canopy structure characteristics. Grain sorghum plants were sampled weekly from emergence to maturity at Big Spring, TX (1986–1987), and Manhattan, KS (1987), to measure the following crop canopy parameters: plant height, stem length, leaf area, stem area, and canopy cover. Manhattan data were used to develop equations that relate canopy structure parameters of grain sorghum to the total above‐groundry weight, and Big Spring data were used to validate those equations. Leaf and stem area distributions with height also were determined. Coefficients of determination of predicted values using the Manhattan equations and Big Spring above‐ground dry weight and the measured Big Spring data ranged from 0.987 for leaf area to 0.922 for stem length. Distribution of leaf and stem area with height remained essentially constant with plant age through the first 7 wk after planting. The equations can be used to supply canopy structure information needed by wind and water erosion prediction models currently under development.