PURPOSE: The purpose of this study was to compare the effects of Graston and self-myofascial release (SMR) techniques on knee joint flexibility, hamstring, and quadriceps strength. METHODS: Twenty subjects with hamstring shortness participated in this study. The subjects were assigned randomly to one of two groups: The Graston technique (GT) group received intervention using a Graston instrument for one minute, and the SMR group performed self-exercises using a foam roll for one minute. The range of motion (ROM) of the knee joint was measured by active knee extension test, and a handheld dynamometer was utilized to collect the hamstring and quadriceps muscle strength. This experiment was performed by two physical therapists. The significant level was set at ${alpha}$=0.05. RESULTS: The results were as follows: 1) The ROM of the knee joint and quadriceps muscle strength were significantly increased in both groups. 2) Hamstring muscle strength was significantly reduced in both groups. 3) There were no significant differences between the GT group and SMR group for any variable. CONCLUSION: The results of this study suggest that SMR is an effective and easy technique for restoring proper muscle length and strength in subjects with hamstring shortness. We recommend that SMR technique be used for treat hamstring shortness in clinical setting and home-program.