Most women convicted of crime are mothers, yet we know little about whether the daily activity of mothering affects women’s criminal behaviour. If mothering reduces opportunities to engage in crime, strengthens informal controls and increases the costs of crime, it should discourage offending. On the other hand, if children create an imperative for resources that women cannot accommodate legally or exacerbate psychological and emotional strains, women may resort to criminal behaviour. Using data from interviews with 259 incarcerated women in Ontario, Canada, we estimate multi-level models focussing on month-to-month changes in women’s responsibilities for children and their offending. We find that mothering is an important ‘local life circumstance’ for reducing women’s involvement in criminal activities.