The rate of females imprisoned worldwide has increased by more than 50% during the last two decades, with recent figures suggesting that, worldwide, the female prison population may still be increasing at a faster rate than males. Despite prevalence rates for psychiatric conditions among female prisoners being significantly higher than males, there is a particular lack of programs specifically designed for women. This preliminary study evaluates the initial effectiveness of a mindfulness and acceptance-based group program in an uncontrolled pragmatic pilot study of a heterogeneous group of incarcerated women with a range of mental health issues. Participants were 59 incarcerated women who engaged in a 10-session group program. Outcome measures comprised the Acceptance and Action Questionnaire-II, Depression Anxiety and Stress Scale, Mindfulness Attention Awareness Scale, and three screening tools derived from the full version of the Patient Health Questionnaire (PHQ-9), to measure depression, binge eating (Patient Health Questionnaire-Binge Eating Disorder [PHQ-ED]), and somatoform disorders (PHQ-15). Results of linear mixed modelling showed improvements in mindfulness and acceptance, and reductions in depression, anxiety, and somatoform symptoms. Furthermore, acceptance and commitment therapy (ACT) was shown to be an acceptable and feasible intervention for female Indigenous Australian prisoners. A mindfulness and acceptance-based group approach appears to be feasible and acceptable in a prison environment for a female prisoners with a range of mental health symptomatology.