Purpose The purpose of this study was to translate and cross-culturally adapt the Achilles Tendon Total Rupture Score (ATRS), a patient-reported outcome measurement (PROM) designed speciically to assess outcomes in patients with Achilles tendon rupture, into the Thai language and then determine its validity and reliability. MethodsThe ATRS was translated into the Thai version (Thai-ATRS) according to internationally recognized guidelines. The study included 50 patients with Achilles tendon rupture from 2003 to 2017. The web-based online assessments were conducted two weeks apart. Construction validity was determined by assessing the correlation between the Thai-ATRS and the Thai version of the Foot and Ankle Outcome Score (Thai-FAOS). Reliability was determined with Cronbach's alpha and intraclass correlation coeicients (ICC). ResultsThe validity test displayed a strong correlation between the Thai-ATRS and the Thai-FAOS (r = 0.87). The reliability test showed good internal consistency with a Cronbach's alpha of 0.95 and excellent internal consistency with an ICC of 0.95, which represented excellent test-retest reliability. The MDC was 10.7 at the individual level and 1.5 at the group level. ConclusionThe Thai-ATRS was demonstrated to be valid and reliable for assessing functional outcomes in Thai patients with Achilles tendon rupture.Level of evidence II.