A seven parent diallel involving spring wheat varieties/lines, Faisalabad-85, Pujab-96, MH-97, Uqab-2000, 6500, 6142 and 7086-1 were evaluated to study gene action for traits like flag leaf area, stomatal frequency, stomatal size, epidermal cell size and leaf venation. All these attributes were conditioned by over dominance type of genetic effects at both population density regimes. The heritability in narrow sense was highest (61%) for stomatal size at both plantings while lowest (12%) for leaf venation at high population density, whereas, heritability in broad sense was maximum for epidermal cell size 97% followed by 94% at high and low population densities, respectively.