Objectives. To examine early impacts of laws that require naloxone to be prescribed to patients at increased overdose risk.Methods. Using data from 2014 to 2018 from a large pharmacy chain, CVS Pharmacy, we examined the effects of naloxone-prescribing mandates 90 days before and after they took effect in Arizona, Florida, Rhode Island, Vermont, and Virginia. We compared the number of naloxone doses initiated directly by prescribers and by pharmacy standing order, prescriber specialty, pharmacies dispensing, and payor type by applying linear models and the χ2 test.Results. Naloxone-prescribing mandates increased pharmacy naloxone provision 255% from 90 days before to after implementation. This approach appeared to engage more prescribers (1028 before to 4285 after), complement ongoing naloxone provision under pharmacy standing orders, expand geographic reach (from 40% to 80% of pharmacies dispensing), and broaden the naloxone payor mix in 4 (P < .05) of 5 states.Conclusions. Mandating the prescribing of naloxone quickly expands access to this life-saving medication for more people in more places. Other states should consider mandating the coprescription of naloxone to individuals at increased risk of overdose.