Post-traumatic stress disorder and deviant peer association have been identified as robust risk factors predicting violent offending. However, there is a dearth of research which has examined interactive effects of these constructs for predicting violence perpetration. The present study utilized data from the Pathways to Desistance study to test for effects. Logistic regression was utilized to examine relationships. Results indicated that there was a significant and positive interaction between post-traumatic stress disorder and deviant peer association for predicting violent offending. Further examination of this relationship indicated that the disorder was a “for better or worse” condition, with low violent offending risk at low levels of deviant peer association and high risk at high levels of deviant peer association.