ObjectivesWe sought to (1) clarify decision needs among suicidal adults with home firearm access; (2) identify accurate, unbiased and acceptable approaches for content and messaging; and (3) develop a tablet-delivered decision aid for firearm storage options.MethodsFollowing international standards, we used stakeholder interviews to develop a decision aid for the decision, ‘what option(s) to choose to reduce home access to firearms for an adult at risk of suicide’. Participants were adults with personal or family history of suicidal ideation or behaviours, firearm ownership or employment in a firearm range or store, involvement in suicide prevention field, or work as emergency department or other healthcare provider.ResultsThrough 64 interviews, we created the ‘Lock to Live’ decision aid, which includes (1) introduction specifying the decision, (2) clarification of preferences and logistics, (3) table of storage options and (4) summary with specific next steps. The final tool had high user acceptability.ConclusionsShould the ‘Lock to Live’ decision aid prove useful in a pilot feasibility trial and subsequent testing, it could enhance lethal means counselling and help prevent firearm suicide.