Australians' use of the English language is influenced by a British educational curriculum, exposure to international television programmes and cultural backgrounds. Hence, adapting research instruments for use with Australian populations can be challenging. This study adapted the United Kingdom's version of the 20-item Diabetes Management Self-Efficacy Scale and tested it psychometrically with Australians. Face validity of the adapted instrument was established through consultation with diabetes educators and people with type 2 diabetes. Data from a convenience sample of 88 people with type 2 diabetes were analysed to determine the psychometric properties of the adapted instrument. The results indicate that the Australian/English version of the instrument is internally consistent, stable over time and it measures self-efficacy. However, there was evidence to show that there might be some redundant items in the scale. Further psychometric testing is warranted with a larger sample to determine whether the scale requires refinement.