The rates of mental illness are significantly higher in prison populations compared to the general community; however, little research has examined the rates of mental illness for cross‐cultural groups of prisoners in Australia. This omission is concerning given the increasingly diverse nature of the Australian prison population. To address this gap in knowledge, the present study aimed to identify rates of key mental health factors and associated psychological processes in a cohort of 191 men from culturally and linguistically diverse, Indigenous Australian and English‐speaking backgrounds who were incarcerated at a maximum‐security prison in Victoria, Australia. We also explored differences in both psychological distress levels and predictors of psychological distress. Although no significant mental health differences were identified cross‐culturally, the results revealed that several mental health factors predicted psychological distress for all prisoners, F(11, 147) = 33.23, p < .001, R2 = .71. The experiences of anxiety and sleep disturbance–related symptoms, β = .34; depressive symptoms, β = .19; posttraumatic stress disorder symptoms, β = .25; and the use of psychological processes, such as avoidance coping, β = .16; and engagement in cognitive fusion, β = .15, all predicted psychological distress. The use of positive thinking as a coping strategy was found to predict a reduced level of psychological distress for prisoners, β = −.13. The findings indicated that the mental health profiles of cross‐cultural groups of prisoners are similar in nature, suggesting that justice involvement may be a more useful predictor than cultural differences concerning psychological health.