Objectives This study assessed the prevalence and correlates of post-traumatic stress disorder (PTSD) among internally displaced people (IDP) in the Qoloji Camp, Somali Regional State, Eastern Ethiopia. Methods A community-based cross-sectional study was conducted from October 20 to November 5, 2021. The study utilized systematic random sampling to identify 410 IDP participants from the Qoloji Camp. PTSD was measured using the PTSD Check-list for DSM-5 (PCL-5). Bivariate analysis was performed to determine the crude odds ratio, and multivariate analysis was used to calculate adjusted odds ratios for associations between PTSD and independent variables. Results A total of 404 participants were interviewed (98.5% response rate). The estimated prevalence of PTSD symptoms was 41.1%. In the multivariate logistic regression analysis, several factors were significantly associated with PTSD: being female (AOR = 2.5, 95% CI = 1.39-4.44), lack of food and water (AOR = 2.2, 95% CI = 1.17, 4.23), destruction of personal property (AOR = 3.1, 95% CI = 1.62-6.09), and experiencing torture or beatings (AOR = 1.8, 95% CI = 1.01-3.28). Conclusion This study found a high prevalence of PTSD symptoms among IDPs, with factors such as female sex, property destruction, deprivation of essential goods and services, and experiences of torture or beatings significantly associated with those symptoms. To address these findings, prioritizing the well-being of IDPs with a specific focus on women, on-site screening, and the establishment of a referral system to facilitate access to specialized care are essential to enhance the overall mental health of such persons.