After the incident of 11 September 2001, military intervention in the Federally Administered Tribal Area (FATA) of Pakistan provides an exogenous shock to different types of violence. To evaluate the deterrence effect of the intervention on monthly tribal violence, I apply a difference-in-differences identification strategy which exploits within-districts variation in the outcome variable (violence) over time. The regression results show that military presence significantly deters tribal violence, that is, it decreases violent incidents by one to five per month. The deterrence effect varies within the given range due to different number of control districts and periods of analysis. These findings are statistically consistent with robustness and falsification tests.