Adhesive bonding is widely used for joining metals or composites in marine, aircraft, automotive, railroad, and civil construction industries. Adhesive single lap joint offers many advantages in terms of time and cost savings, has good damping characteristics, and provides high joint strength compared to another conventional joint. In this study, an analysis of free vibration of composite single lap joint has been carried out using by modal analysis solver i.e. ANSYS. Optimization study is then carried out to obtain the optimal design for vibration resistance. The simulation results of the natural frequency for each variation of joint thickness and overlap length are obtained through this study. The results show that increasing thickness and overlap length will increase the value of natural frequency as well, thus giving better vibration resistance. It is found that the optimum thickness and overlap length are 2.54 mm and 70 mm, respectively. The results point out the importance of joint thickness and overlap length for the vibration resistance of single lap joint of composite plates.