BACKGROUND: People who have had hemiplegic stoke generally move more weight to the unaffected side than the affected side, resulting in asymmetrical posture and decreased ability in walking. OBJECTIVES: This study sought to investigate the effect of inducing a weight shift to the affected side by raising the shoe height of the less affected side using an insole during the execution of treadmill training on gait ability in people with chronic stroke. METHODS: The subjects were randomly assigned into two groups: insole on less affected side for execution of treadmill walking training (ILTW) group and normal treadmill training (NTW) group. The treadmill training was conducted for 30 minutes per session, 5 times a week, for 4 weeks. A gait analyzer based on body center, Functional Gait Assessment (FGA), Figure-of-Eight Walk Test (F8WT), and 6 min Walk Test (6 MWT), was measured before first intervention and after twentieth treadmill training intervention (Trial registration number is KCT0003830). RESULTS: The results revealed statistically significant differences between the two groups in the Speed, Cadence, Stride Length/Height, Stride Length, Double Support Duration, Single Support Duration, FGA, F8WT, and 6 MWT of the gait test. In the ILTW group, statistically significant improvements were observed in the Speed, Stride Length/Height, Stride Length, Stance Phase Duration, Swing Phase Duration, Double Support Duration, Single Support Duration, FGA, F8WT, and 6 MWT after execution of training, while in the NTW group, statistically significant improvements were observed only in Speed, Cadence, FGA, F8WT, and 6 MWT. CONCLUSIONS: ILTW, more than NTW, may improve walking ability in people with chronic stroke as it increases the weight-support ratio by adjusting the shoe height of the unaffected side using an insole.