A better understanding of the influence of aggregate gradation on the shear resistance and volumetric properties of asphalt mixtures is needed to maximize the shear and rutting resistance in asphalt mixtures. Eighteen mixtures were prepared with different coarse aggregate (> 2.0 mm) gradations ranging from Stone Matrix Asphalt (SMA) to those corresponding to the maximum density line. The Gyratory Shear (Gs measurements indicated the gradation of the coarse aggregate fraction (> 2.0 mm) was related to the shear resistance of the mixtures. Coarseness, shape, and position of the gradation curve relative to the maximum density line affected the shear resistance. Mixtures including both coarse and fine aggregate fractions verified the test results obtained from the coarse-aggregate only mixtures. It was evident that coarse aggregate gradations controlled the shear resistance of the mixtures even though fine aggregate dilated the coarse aggregate structure. Crumb rubber modified (CRM) asphalt binders were generally found to have little effect on the air void content and shear resistance (Gs) of coarse- graded (e.g., SMA) mixtures.