The psychometric properties of the Generalized Trust Scale (GTS) are well established. Furthermore, previous studies have found that the GTS is positively associated with better mental health and lower distress, and the literature finds that trust is good for mental health. However, current literature does not have any psychometric evidence concerning the Persian GTS. This study translated the GTS into Persian and validated its psychometric properties. After translating the GTS into Persian using robust and standardized translation procedure, 1200 Iranians (mean age = 34.83 years; 583 [48.6%] males) completed the GTS, along with the Hospital Anxiety and Depression Scale (HADS), Short Form-12 (SF-12), and Oxford Happiness Questionnaire Short Form (OHQ-SF). The factor structure of Persian GTS was confirmed by a unidimensional model with a method factor (comparative fit index = 0.998; Tucker-Lewis index = 0.992). The unidimensional model was also supported by Rasch analysis (mean square = 0.75 to 1.31). Other properties of the Persian GTS were satisfactory. More specifically, test-retest reliability was good (intraclass correlational coefficient = 0.865), internal consistency was good (alpha = 0.881), and concurrent validity was supported (standardized beta = - 0.086 with depression in the HADS [p = 0.045]; = - 0.162 with anxiety in the HADS [p < 0.001]; = 0.077 with mental component score in the SF-12 [p = 0.044]; = 0.624 with OHQ-SF [p < 0.001]). The six-item Persian GTS has promising psychometric properties and can be an effective measure to assess trust among Iranians.