IMPORTANCE Recent evidence indicates a high prevalence of child abuse exposure in modern US veterans, which may explain in part their higher likelihood of suicide relative to civilians. However, the relationship between child abuse exposure and suicide-related outcomes in military personnel relative to civilians is unknown. Furthermore, the associations among deployment-related trauma, child abuse exposure, and suicide-related outcomes in military personnel have not been examined. OBJECTIVES To determine whether child abuse exposure is more prevalent in Canadian Armed Forces (CAF) personnel compared with the Canadian general population (CGP); to compare the association between child abuse exposure and suicidal ideation, suicide plans, and suicide attempts among the CAF and CGP; and to determine whether child abuse exposure has an additive or interaction effect on the association of deployment-related trauma and past-year suicidal ideation and suicide plans among Regular Forces personnel. DATA, SETTING, AND PARTICIPANTS Data were collected from the following 2 nationally representative data sets: the 2013 Canadian Forces Mental Health Survey (CFMHS) for the CAF (8161 respondents; response rate, 79.8%) and the 2012 Canadian Community Health Survey-Mental Health (CCHS-MH) for the CGP (23 395 respondents; response rate, 68.9% [of these, 15 981 age-matched participants were drawn]). Data were collected from April 15 to August 31, 2013, for the CFMHS and January 2 to December 31, 2012, for the CCHS-MH. Data were analyzed from October 2014 to October 22, 2015. Statistical weights were applied to both data sets. MAIN OUTCOMES AND MEASURES Child abuse exposure, including physical abuse, sexual abuse, and exposure to intimate partner violence, and deployment-related trauma were assessed in relation to suicide-related outcomes. RESULTS Data were analyzed from 24 142 respondents aged 18 to 60 years (Regular Forces, 86.1% male and 13.9% female; Reserve Forces, 90.6% male and 8.9% female; and CGP, 49.9% male and 50.1% female). Any child abuse exposure was higher in the Regular Forces (47.7%; 95% CI, 46.4%-49.1%) and Afghanistan mission-deployed Reserve Forces (49.4%; 95% CI, 46.3%-51.5%) compared with the CGP (33.1%; 95% CI, 31.8%-34.4%). All types of child abuse exposures were associated with increased odds of suicidal ideation, suicide plans, and suicide attempts in the CGP (range of adjusted odds ratios [AORs], 3.0 [95% CI, 2.3-3.9] to 7.7 [95% CI, 5.7-10.3]; P < .05) and CAF (range of AORs, 1.7 [95% CI, 1.0-2.9] to 6.3 [95% CI, 4.2-9.5]; P < .05), with many associations significantly weaker in military personnel relative to civilians. Additive effects for past-year suicide ideation (AOR, 2.7; 95% CI, 1.8-4.2) and past-year suicide plans (AOR, 4.6; 95% CI, 2.3-9.2) but not interactive effects for past-year suicide ideation (AOR, 1.2; 95% CI, 0.7-2.2) and past-year suicide plans (AOR, 0.8; 95% CI, 0.3-2.2) were noted between deployment-related trauma and child abuse exposure among Regular Forces personnel. CONCLUSIONS AND RE...