Background Many prisoners rationalise criminal behaviour, and this type of thinking has been linked to recidivism. Correctional programmes for modifying criminal thinking can reshape how offenders view themselves and their circumstances. Aim Our aim was to test whether participation in a cognitive‐based curriculum called Steps to Economic and Personal Success (STEPS) was associated with changes in criminal thinking. Methods The STEPS curriculum is delivered in 15 video‐based facilitated classes. A pre‐intervention/post‐intervention survey design was applied to 128 adult male prisoners who completed the programme. Criminal thinking was measured by the Texas Christian University Criminal Thinking Scale, a self‐report instrument with the six domains: entitlement, justification, power orientation, cold heartedness, criminal rationalisation and personal irresponsibility. Results Participants had lower scores in most of the criminal thinking domains after the intervention than before, with largest reductions in justification and power orientation. Conclusion Findings provide evidence that attitudes to crime can be changed in a correctional setting, and the programme under study shows promise as an effective intervention for changing these attitudes among prisoners. Future research should build on these findings to examine whether and how such changes are related to desistance from offending behaviours. Copyright © 2017 John Wiley & Sons, Ltd.