ImportanceSecure firearm storage may help reduce firearm injury and death. Broad implementation requires more granular assessments of firearm storage practices and greater clarity on circumstances that may prevent or promote the use of locking devices.ObjectiveTo develop a more thorough understanding of firearm storage practices, obstacles to using locking devices, and circumstances in which firearm owners would consider locking unsecured firearms.Design, Setting, and ParticipantsA cross-sectional, nationally representative survey of adults residing in 5 US states who owned firearms was administered online between July 28 and August 8, 2022. Participants were recruited via probability-based sampling.Main Outcomes and MeasuresFirearm storage practices were assessed via a matrix provided to participants in which firearm-locking devices were described both via text and images. Locking mechanisms (key/personal identification number [PIN]/dial vs biometric) were specified for each type of device. Obstacles to the use of locking devices and circumstances in which firearm owners would consider locking unsecured firearms were assessed via self-report items developed by the study team.ResultsThe final weighted sample included 2152 adult (aged ≥18 years), English-speaking firearm owners residing in the US; the sample was predominantly male (66.7%). Among the 2152 firearm owners, 58.3% (95% CI, 55.9%-60.6%) reported storing at least 1 firearm unlocked and hidden, with 17.9% (95% CI, 16.2%-19.8%) reporting storing at least 1 firearm unlocked and unhidden. Gun safes were the most frequently used device both among participants who use keyed/PIN/dial locking mechanisms (32.4%; 95% CI, 30.2%-34.7%) and those who use biometric locking mechanisms (15.6%; 95% CI, 13.9%-17.5%). Those who do not store firearms locked most frequently noted a belief that locks are unnecessary (49.3%; 95% CI, 45.5%-53.1%) and a fear that locks would prevent quick access in an emergency (44.8%; 95% CI, 41.1%-48.7%) as obstacles to lock usage. Preventing access by children was the most often reported circumstance in which firearm owners would consider locking unsecured firearms (48.5%; 95% CI, 45.6%-51.4%).Conclusions and RelevanceIn this survey study of 2152 firearm owners, consistent with prior research, unsecure firearm storage was common. Firearm owners appeared to prefer gun safes relative to cable locks and trigger locks, indicating that locking device distribution programs may not match firearm owners’ preferences. Broad implementation of secure firearm storage may require addressing disproportionate fears of home intruders and increasing awareness of the risks associated with household firearm access. Furthermore, implementation efforts may hinge on broader awareness of the risks of ready firearm access beyond unauthorized access by children.