Objectives. To culturally adapt and translate the Disabilities of Arm, Shoulder, and Hand questionnaire into Hindi (DASH-H) and assess its reliability, validity, and responsiveness in adult patients with shoulder tendonitis.Study Design. Descriptive methodological research, using longitudinal design.Setting. Outpatient clinic.Participants. 30 adult patients aged 53.3 ± 6.9 y with shoulder tendonitis.Data Analyses. DASH-H, visual analogue scales for pain (VAS-P) and disability (VAS-D), and shoulder active range of motion (AROM) were assessed at baseline, 2-3 days later, and 4-5 weeks after baseline. Intraclass correlation coefficients (ICC) assessed test-retest reliability of these scales and responsiveness was examined by calculating effect sizes (ES) and standardized response means (SRM). Cronbach’s alpha (CA) was used to examine internal consistency of DASH-H. Convergent construct validity of DASH-H with VAS scales and shoulder AROM was determined using Pearson’s Correlation Coefficients ().Results. DASH-H demonstrated good test-retest reliability and internal consistency (ICC and CA both > 0.75) and excellent responsiveness (ES = 2.2, SRM = 6.1). DASH-H showed high concordance (,) with AROM-flexion and moderate concordance (,) with VAS scales and AROM-external rotation.Conclusion. Analyses indicate that DASH-H demonstrates good test-retest reliability, validity, and responsiveness in patients with shoulder tendonitis.