Abstract Objectives To examine associations between post-traumatic stress disorder (PTSD) and nutrition factors among Canadian-born and immigrant adults. Methods The sample included participants of the Canadian Longitudinal Study on Aging (CLSA) (n = 27,211; 45–85 years) categorized by ethnicity (native white, native minority, immigrant white, and immigrant minority). PTSD was measured using the Primary Care PTSD tool. Nutrition factors included nutrition status indicators (anthropometrics, body fat %, handgrip strength, nutrition risk, sarcopenia, bone mineral density, and iron deficiency anemia) and dietary intakes (fiber, pulses and nuts, fat, omega-3 fatty acids, fruits and vegetables, fruit juice, calcium/vitamin D, salty snacks, pastries, and chocolate bars). Covariates included socioeconomic and health-related variables. Binary logistic regression analysis was conducted. Results Compared to white Canadians born in Canada, immigrant minority groups had a higher likelihood of PTSD (OR = 1.47, 95% CI 1.14–1.90, P < 0.001). Nutrition factors associated with PTSD included high nutrition risk (OR = 1.60, CI 1.41–1.80, P < 0.001), intakes of pulses and nuts (≥ one source; ORs 1.50–1.16, P's-< 0.05), pastries or chocolate (≥ 2/3 of a standard bar) (ORs = 1.35–1.37, P's < 0.05), and fiber (2–3 sources daily; OR = 0.83, CI 0.69–1.00, P < 0.05), as well as high waist-to-height ratio (OR = 0.91, CI 0.69–0.97, P < 0.05). Other factors included income (<C$100,000/yr; ORs 1.39–2.58, P's < 0.001), being widowed, divorced, or separated (OR = 1.35, CI 1.10–1.65, P < 0.05), having multiple chronic conditions (ORs = 1.76–3.34, P's < 0.001), experiencing chronic pain (OR = 1.64, P < 0.001), and smoking (OR = 1.22, P < 0.001). Conclusions Many nutrition-related factors contribute to PTSD in mid-age and older adults suggesting that targeted nutrition interventions within comprehensive programming will likely help prevent or manage PTSD. Funding Sources MITACS and Fulbright Canada.