As more states adopt recreational marijuana laws (RMLs), concerns remain about how expanded cannabis access may affect child welfare. This study presents new causal evidence on the relationship between RMLs and substantiated cases of child maltreatment. Leveraging a generalized difference- in-differences framework that exploits the staggered rollout of RMLs across states, I first show that legalization accompanied by recreational dispensary openings increases the rate of adult marijuana use in treated states relative to control states. I then find that RML adoption with dispensary access leads to an increase of approximately two cases of substantiated child maltreatment per 1,000 children. Supplementary evidence from time-use data suggests that reductions in parental caregiving time may help explain this pattern. These findings suggest that increased child maltreatment among families exposed to expanded cannabis access may be an unintended consequence of marijuana legalization.