Hamstring muscle tightness is blamed for lumbar disc prolapse. There is a lack of consistency about effect of hamstring muscle tightness on lumbar angle. This may be attributed to variations in laterality of the hamstring tightness; being unilateral or bilateral. Purpose: to examine the effect of laterality of hamstring muscle tightness on lumbar angle in adults with lumbar disc prolapse (LDP). Methods: This cross-sectional study included forty-five patients of both genders complained from lumbar disc prolapse (LDP). They were divided into three groups; group A included 15 patients with bilateral hamstring tightness (active knee extension angle >-20 in both legs), group B included 15 patients with unilateral hamstring tightness (active knee extension angle >-20 in one leg), and group C included 15 patients with normal hamstring tightness (active knee extension angle ≤-20 in both legs). Lumbar curve angle was measured by Cobb, s angle (on lateral radiographs) and hamstring muscle tightness was measured with a standard goniometer using active knee extension test. Results: Lumbar lordotic angle not significantly differs between the three groups of hamstring muscle tightness (unilateral, bilateral, and normal) (P-value = 0.87). Conclusion: Hamstring muscle tightness does not seem to affect lumbar lordotic angle even after controlling for laterality in patients with LDP. Stretching of hamstring muscle may be not important for these patients, but this needs further randomized clinical trial to prove