Suicide is the second leading cause of death among adolescents in the U.S., and risk factors include child maltreatment (CM), especially physical and emotional abuse, and in-home firearm availability (‘availability’). However, research examining availability among adolescent populations at-risk for CM is limited. This study examines availability in this population, the association between CM and availability, and availability among adolescents experiencing suicidal ideation. A multivariable modified Poisson regression model assessed the relationship between CM by age 12 and availability at age 14 using data from the Longitudinal Studies of Child Abuse and Neglect (n = 1,354 families). Approximately 11.61% of adolescents reported availability, and physical abuse increased the risk of availability (aRR = 1.94; 95% CI [1.22, 3.08]). Over one-quarter (27.50%) of adolescents with suicidal ideation at age 16 reported availability. Child welfare-involved families are often referred to interventions. Future research and prevention efforts should explore augmentation of these programmes with firearm safe storage guidance.