What is the relationship between armed violence and patriarchal values? This question is addressed with the help of a survey of young men in the conflict-affected southern provinces of Thailand. In Study 1 we find that men with more patriarchal values are more prone to volunteer for paramilitary service. Study 2 uses a natural experiment made possible by the conscription lottery in Thailand to compare survey responses of men who were involuntarily enlisted to do Military Conscription Service (treatment group) with the responses of men who participated in the lottery but were not enlisted (control group). We find no difference between the treatment and control groups in patriarchal values. We conclude that patriarchal values drive voluntary participation in armed conflict, whereas military service as a conscript in a conflict zone does not cause patriarchal values.