Marriage is associated with a reduced rate of criminal recidivism, but the underlying mechanisms have only partly been elucidated. We seek to clarify the nature of the association between marriage and recidivism and how that relationship may be moderated as a function of gender, deviance of spouse, a history of violence and familial risk.

We utilise a longitudinal cohort design consisting of Swedish men (n = 239 328) and women (n = 72 280), born between 1958 and 1986, who were convicted of at least one crime before age 20 and were not married prior to age 20. The analyses used Cox regression with marriage as a time-dependent covariate. We also perform co-relative analyses in sibling and first cousin pairs.

Marriage after a first crime substantially reduces risk of recidivism in both males (hazard ratio (HR) with key covariates and 95% confidence intervals 0.55, 0.53–0.57) and females (HR = 0.38, 0.34–0.42), although the effect is stronger in females. Marriage to a deviant spouse increases recidivism rates in males. In males, a history of violent criminality and high familial risk, respectively, decrease and increase sensitivity to the protective effect of marriage on recidivism. Consistent with a causal effect of marriage on recidivism, marriage was associated with a decline in risk for criminal relapse comparable with that in the population in both male–male sibling pairs (raw HR = 0.53, 0.45–0.62) and cousin pairs (HR = 0.55, 0.47, 0.65) concordant for prior convictions.

The protective effect of marriage on risk for criminal recidivism is likely largely causal and is of importance in both males and females. Those at high familial risk for criminal behaviour are more sensitive to the protective effects of marriage.