The aim of this study was to develop and test the construct and content validity, internal consistency of the Family‐Carer Diabetes Management Self‐Efficacy Scale (F‐DMSES). A sample of 70 Thai individuals who cared for those living with type 2 diabetes mellitus (T2DM) in a rural community in Thailand was included in the study. Data were collected by a questionnaire survey in January 2014. The F‐DMSES was initially derived from the DMSES, with subsequent forward and backward translations from and to English and Thai languages.