The last 4 decades of conflict in Afghanistan resulted in incalculable deaths, injuries, and millions of displacements. Although there are routine reports on casualties of the warfare, the information on its long-term psycho-social sequelae is somehow discounted. This study aimed to assess post-traumatic stress disorder (PTSD) probability and its associated factors among parents who live in Kandahar, the southern province of Afghanistan, and lost at least one child to armed conflict. We conducted a health-facility-based cross-sectional study involving 474 bereaved parents in Kandahar province from November/2020 to January/2021. The questionnaire was composed of sections on socio-demographic characteristics and mental and medical histories of the parent, features of the traumatic event and the time elapsed since then, age and gender of the lost child, and PCL-5. We performed multivariable logistic analysis to determine factors associated with PTSD probability in such parents. A staggering number of the parents (430; 90.72%) scored > 33 on PCL-5 denoting presence of probable PTSD. We noticed that several attributes of the bereaved parents (rural residence [AOR = 3.71 (95% CI 1.37–9.97)], older age [AOR = 2.41 (95% CI 1.03–5.57)], experiencing more than one traumatic event [AOR = 2.91 (95% CI 1.05–7.94)], pre-existing medical condition [AOR = 3.5 (95% CI 1.55–8.05)], and losing a < 5-years-old child [AOR = 2.38 (95% CI 1.16–4.70)] were significantly associated with PTSD probability. We assert that a very high number of bereaved parents are susceptible to probable PTSD. This finding signifies the eminent necessity of mental health services in such settings and provides implicit insights to relevant humanitarian assistance providers.