Joining methods and suitable geometry selection become an important role in the bonding of composites. The fatigue strength of adhesively bonded joint of thick woven type laminated E-glass/ Polymer matrix composites consist of 22 layers with a layer thickness of 0.5 mm was investigated experimentally. Frequency was kept constant at 10 Hz for all experiments, while the load ratio was equal to 0.1, resulting in a tension-tension fatigue loading. Octagonal and pentagonal tongue and groove joint design were used in order to join thick composite materials. Experimental results and SEM analysis of present study indicated that fatigue strength was strongly influenced by the geometry of joint design. Claw length and claw width defined in the design were found to have a significant effect on fatigue strength of adhesively bonded joints. The octagonal design showed almost two times higher fatigue strength than pentagonal joint design.