High strength synthetic fiber-reinforced polymer composite beams are commonly failed by kinking at their compressive faces. Partial replacement of the fibers at the weaker faces with stronger fibers to produced hybrid fiber composite systems can improved their performance. In addition, their applied shear-to-normal stress ratio can affect their The effect of span-to-depth ratio, S/d, on the flexural properties of hybrid S2/E-fiber-reinforced epoxy composites has been investigated. S/d of 16, 32 and 64 have been selected, and six plates of different hybrid ratios, i.e. 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, have been fabricated using compression molding technique in vacuum environment. Before being stacked depending upon the hybrid ratio and pressed in the mold, the fibers were embedded into the matrix to produce glass/epoxy prepreg sheets possessing a thickness of 0.45 mm. The thickness of the plates being produced is 2 mm. Flexural test was carried out in accordance with the ASTM D790 in an Instron Universal Testing Machine at room temperature and applying strain rate of 1 percent/minute. Five specimens have been tested for each case as recommended by the standard. The specimens were cut from the plates using a diamond-tipped circular saw blade rotating at 10,000 rpm. A number of failed specimens from the flexural test were randomly selected to be prepared for micrograph capturing under an optical microscope. It was reveals that the larger the S/d the higher flexural strength and flexural modulus. To the contrary, slight decrease in flexural failure strain was noted with the increase of S/d. All specimens were found to fail at their compressive sides by fiber and matrix crushing. At S/d =16, fail was initiated with longitudinal cracks followed by fiber and matrix crushing, but longitudinal crack was not observed for longer beams.