CONTEXT: Hip muscle imbalance, especially between gluteal muscles and tensor fasciae latae (TFL), is one of the risk factors for developing low back pain which should be considered in rehabilitation programs. This study compared the effect of exercises with gluteal-to-TFL muscle activation index above and below 50 on pain intensity, disability, and lower limbs' range of motion (ROM) in patients with nonspecific chronic low back pain. DESIGN: A semiexperimental intervention study with a pretest and posttest. METHODS: A total of 45 patients with nonspecific chronic low back pain were randomly divided into 2 experimental groups of gluteal-to-TFL muscle activation index above 50 (n = 15), below 50 (n = 15), and a control group (n = 15). Pain intensity (visual analog scale), disability (Roland-Morris Disability Questionnaire), and lower limbs' ROM including hip extension, hip abduction, hip external rotation, and knee extension (goniometer) were assessed at pretest and after 8 weeks of intervention. RESULTS: Within-group comparison showed significant improvement of pain, disability, and ROMs in both experimental groups. No significant changes were observed in the control group. In between-group analysis, significant differences were observed in group of gluteal-to-TFL muscle activation index above 50 for only pain (P = .03) and disability (P = .01). For ROMs, although clinical improvement of lower limbs' ROMs was higher in group of gluteal-to-TFL muscle activation index above 50, no statistically significant differences were found between 2 experimental groups. Both experimental groups were superior to the control group for all outcomes. CONCLUSIONS: Findings indicate the statistically and clinically superior effectiveness of exercises with a gluteal-to-TFL muscle activation index above 50 in the reduction of pain and disability. Based on the clinical significance of exercises with a gluteal-to-TFL muscle activation index above 50 for improving ROMs, utilizing specific exercises that more activated gluteal muscle compared to TFL is recommended for patient with restricted lower limbs' ROMs.