The US Food and Drug Administration approved Narcan, a nasal spray formulation of naloxone, for sale as an over-the-counter (OTC) medication in March 2023. The purpose of OTC approval was to improve naloxone accessibility to reduce opioid overdoses; however, research has not yet evaluated whether naloxone's availability and cost changed since this policy was implemented. To evaluate whether the accessibility and cost of naloxone at North Carolina community pharmacies changed after OTC naloxone became available and whether cost and availability varied by pharmacy type and urbanicity. This longitudinal telephone-based secret shopper survey study included a stratified sample of 202 North Carolina community pharmacies, including health department, independent, and chain pharmacies. There were 2 separate data collection efforts from March to April 2023 (before OTC naloxone could be sold at pharmacies) and November 2023 to January 2024 (after OTC naloxone was sold at pharmacies). OTC naloxone first became available for sale at community pharmacies in September 2023. The main outcomes were same-day availability of naloxone without a clinician-issued prescription and the quoted out-of-pocket cost for cash-paying patients. Data were collected from 192 pharmacies. Same-day naloxone availability increased from 42.2% (81 of 192) before OTC naloxone availability to 57.8% (111 of 192) after (P < .001). The mean (SD) quoted out-of-pocket cost decreased from $90.93 ($42.6) pre-OTC availability to $62.67 ($41.0) post-OTC availability (P < .001). Independent pharmacies had higher mean (SD) costs than chain pharmacies in both the pre-OTC phase ($109.47 [$37.90] vs $86.40 [$35.70]; P < .001) and post-OTC phase ($77.59 [$38.90] vs $57.74 [$35.90]; P = .004). Out-of-pocket costs did not differ by urbanicity in the pre-OTC phase; however, mean (SD) costs were higher at suburban ($88.67 [$66.80]) and rural ($65.43 [$35.00]) pharmacies compared with urban pharmacies ($53.58 [$29.00]) in the post-OTC phase (P = .003). The Food and Drug Administration's approval of OTC naloxone nasal spray contributed to an increase in pharmacy-based availability of naloxone and a reduction of its cost for cash-paying patients. Cost was higher at independent pharmacies compared with chain pharmacies and lower in urban pharmacies compared with suburban and rural pharmacies.