Against the backdrop of scholarship on the internal causes of conflicts, this study examined how government institutions externally fuel persistent communal conflicts (PCC) in Nigeria. With multiple methods and triangulation of sampling techniques, we examined 12 pairs of warring communities, 4464 respondents, and 18 key interviewees. The causes of PCC were misapplication of constitutional/legal instruments and biased enforcement administration that favored one community over the other. Through matrix correlation, institutions like constitution and legal mechanisms, peace‐building mechanisms, and the enforcement agents' roles fuelled PCC among the warring communities. This correlation has a negative relationship that led to the people's loss of confidence in the umpires, vengeance, jungle justice and intolerance among the warring communities. We concluded that these institutional lapses created a class of disadvantaged and aggressive victims who have become intolerant of other communities. There is a need to sanitize governmental institutions to treat communal disputes with justice and fairness.