Introduction: Arm and hand function deficits are commonly in people with multiple sclerosis (PwMS). The Arm Function in Multiple Sclerosis Questionnaire (AMSQ) is a novel self-administered instrument specifically developed to evaluate upper limb function in MS. The aim of this study was to translate and adapt the AMSQ into Italian and to assess its psychometric properties in PwMS. Validity (structural, construct, and known-groups) and reliability (internal consistency, test-retest, and measurement error) were assessed. Materials and methods: From June 2017 to February 2018, a prospective cohort of PwMS among those followed as outpatients at the Rehabilitation Services of the Italian Multiple Sclerosis Society (AISM) of Genoa, Padua, and Vicenza was involved in the study. Construct validity of AMSQ was determined by examining correlations with the Italian version of ABILHAND, Modified Fatigue Impact Scale (MFIS), and Functional Independence Measure (FIM). Results: A total of 234 PwMS were enrolled. The mean AMSQ total score was 67.3 (SD = 38.4). Factor analysis results suggested one factor. As expected, moderate to high correlation coefficients were found between AMSQ and ABILHAND (− 0.79), MFIS (0.50) and its subsets, and FIM (− 0.60) and its subsets involving upper limb functioning. PwMS with higher EDSS reported worse total score of AMSQ than patients with low disability. The internal consistency of the 31 items was high (Cronbach’s α, 0.98). Test-retest reliability, as measured with ICC, was 0.96 (95% IC, 0.93–0.98), and measurement error was about 8.3 points showing good reliability. Discussion: AMSQ has been adapted and validated, it is a reliable questionnaire for Italian PwMS.