In this article, the bearing strengths, failure modes, and joint geometries of woven glass-epoxy prepreg composite mechanically fastened joints with clearance subjected to preload moments were studied experimentally. Two different geometrical parameters were investigated. Therefore; the edge distance-to-pin diameter (E/d) and width-to-pin diameter (W/d) ratios were systematically varied and corresponding failure modes and loads were defined. The preload moments were selected as 0 and 2 Nm. The experiments were also carried out under a clearance for the diameters of the pin and the circular hole for 5 and 5.2 mm, respectively. Damage of specimens with clearance was examined using scanning electron microscope. The experimental results obtained from joints with clearance were compared with the earlier results that were not including clearance. It was observed that the effect of clearance on the bearing strength of mechanically fastened joints is significant. The failure loads of the composite joints with preload moment were larger than those of the composite joints without preload moment. Also, if geometrical parameters of mechanically fastened composite joints are varied, the failure modes and loads are strictly influenced from this variation.