Purpose This study had the following two aims (1) to examine the moral reasoning abilities of four groups of people: (i) men and women with intellectual disabilities (IDs) who had a documented history of criminal offending and (ii) men and women with IDs with no known history of criminal offending, and (2) to examine the relationship between emotional and behavioural problems and moral reasoning. It was predicted that (1) there would be no significant difference between the moral reasoning of men and women with IDs, (2) men and women with IDs who are not offenders will have ‘developmentally immature’ moral reasoning in comparison to offenders, and (3) moral reasoning will significantly predict emotional and behavioural problems. Methods Sixty‐eight people with IDs were invited to take part in this study and spread across four groups: (1) men with IDs who had committed criminal offences, (2) women with IDs who had committed criminal offences, (3) men with IDs who had no known history of criminal offending, and (4) women with IDs who had no known history of criminal offending. Participants were asked to complete measures of intelligence, moral reasoning, and emotional/behavioural problems. Results As predicted, men and women did not have different moral reasoning, but offenders did have ‘developmentally more mature’ moral reasoning than non‐offenders. Women had higher levels of physical and verbal aggression, while offenders, generally, had higher levels of psychopathology. Women with a history of criminal offending had higher levels of sexually inappropriate behaviour compared to men and women in the community. Moral reasoning significantly predicted emotional and behavioural problems. Conclusions Further work in this area is needed, and interventions that aim to address a moral developmental ‘delay’ may be beneficial in reducing recidivism among this population.