Despite unsafe firearm storage being the leading cause of firearm-related injury/death among young children (under age 5 years), we lack information regarding how to develop and deliver effective messaging to encourage parents to adopt firearm safety practices in early childhood. This study will employ a mixed methods, developmentally-informed approach to improve our understanding of the scope of and motivations for gun ownership, storage, and use among parents with young children. We will assess parents’ mental models of firearm safety and injury prevention during early childhood and apply the lessons learned to develop a parent-engaged intervention delivered by trusted messengers and precision messaging tailored for firearm injury prevention in early childhood.