This study aimed to investigate acculturation's direct and mediated effects on HbA_1c levels in individuals with type 2 diabetes from Arabic-speaking countries that are members of the Arab League who have emigrated to Australia. In this multicentre cross-sectional study, we recruited 382 Arabic-speaking immigrants who were born in any of the 22 countries of the Arab League and who had type 2 diabetes from different healthcare settings in Australia. HbA_1c levels were retrieved from medical records. A validated self-report questionnaire was used to assess behavioural and psychosocial outcomes. Acculturation was measured using the General Acculturation Index and the Adherence to Traditional Values tool. We used structural equation modelling to test mediation hypotheses. Participants had a mean HbA_1c value of 63.9 mmol/mol (8.0%), a low acculturation level (mean±SD: 1.9±0.6; range: 1-5) and highly adhered to traditional values (mean General Acculturation Index value: 3.7±0.7; range: 1-5). Higher HbA_1c was associated with lower acculturation levels (Pearson correlation coefficient [r] = -0.32, p<0.01) and higher adherence to traditional values (r=0.35, p<0.01). Self-efficacy, health literacy and self-care activities partially mediated the relationship between acculturation and HbA_1c. Among Arab immigrants in Australia with type 2 diabetes, the degree of acculturation is related to glycaemic control, suggesting possible avenues for new interventions.