Aggression is an important mental health challenge in prison environments. Although sports participation can be effective in reducing aggression, evidence regarding the relationship between sports participation and dimensions of aggression among prison conscripts is limited. Therefore, this study aimed to examine the relationship between sports participation and dimensions of aggression among conscripts serving in prisons. The statistical population consisted of all conscripts serving in prisons of Mazandaran Province. Soldiers from three prisons in Sari, Tonekabon, and Babol were selected as the study sample using cluster random sampling. Data were collected using demographic information questionnaires, the Sherkly (1999) Sports Participation Questionnaire, and the Makarowski et al. (2012) Aggression Questionnaire, which includes three dimensions of go ahead, tripping up, and assertiveness. Data were analyzed using descriptive statistics, Pearson correlation, multivariate analysis of variance (MANOVA), and Scheffé post-hoc test at a significance level of 0.05 using SPSS version 26. The results showed that soldiers with moderate, high, and very high levels of sports participation had significantly lower levels of go ahead, tripping up, and assertiveness than those in the very low and low sports participation groups. Furthermore, sports participation explained 41.3% of the variance in aggression. The findings indicated that moderate-to-high sports participation can be considered an appropriate strategy for reducing aggression among soldiers. Therefore, relevant authorities should plan to increase soldiers’ participation in sports activities, provide necessary facilities, and create opportunities for regular and purposeful participation in sports to utilize its potential for promoting soldiers’ mental health.