This study aimed to translate the Gait Assessment and Intervention Tool (G.A.I.T.) into Japanese and evaluate its reliability and validity. Translation and adaptation followed established cross-cultural guidelines. To assess reliability and validity of Japanese versions of the G.A.I.T, a cohort design was implemented. Sixty-three stroke patients participated in interrater reliability and validity assessments, and 50 patients in the test-retest evaluation. Reliability and validity were evaluated using intraclass correlation coefficients (ICC) and Pearson's correlation coefficients, respectively. The Japanese G.A.I.T. demonstrated excellent reliability in interrater (ICC = 0.975) and retest (ICC = 0.988). Significant correlations were observed between the G.A.I.T. scores and Fugl-Meyer Assessment-Lower Extremity (r = -0.774), Functional Ambulation Category (r = -0.720), Functional Independence Measure motor scores (r = -0.647), functional independence measure mobility (r = -0.688), and comfortable walking speed (r = -0.839). These findings suggest that the Japanese version of the G.A.I.T. is a reliable and valid assessment tool for evaluating gait coordination in Japanese stroke survivors.