Stigmatic attitudes appear to vary across different mental health diagnoses, and offenders with mental illness have been shown to elicit more negative stigmatic attitudes than offenders without mental illness. Stigma and discrimination can have detrimental effects on an individual's recovery, treatment and even employment opportunities. This systematic review aimed to report the commonality of research into stigma towards offenders with mental health conditions, to explore if different mental health diagnoses were associated with differential rates of stigma in offenders, and to ascertain which psychometric measures have been used to capture such stigmatic attitudes. Twelve studies were included in the review with varied populations and study locations. The vast majority reported negative stigmatic attitudes towards offenders with mental illness when compared to control groups, with neither a criminal history nor a mental illness. Results also indicated that the diagnoses with particularly high levels of stigma were psychopathy and schizophrenia. Psychometric measures used to capture stigma varied considerably and rarely was the same measure used across studies which limited comparisons. This review highlights a number of key points for advancing research in the area which are discussed along with strengths and limitations.