Study follows a model having OS as predictor variable, OCB as an outcome variable and OC as mediating variable which has no evidence in the existing literature. To examine about this model 220 respondents were investigated in lower level administrative staff of higher public sector educational institutions in Khyber Pakhtunkhwa (KP) Pakistan. Already established instruments were used to measure the constructs of the study. The data were passed through correlation and regression analyses. The results demonstrated negative effect of OS on OCB which means that with increase in employees’ silence their involvement in extra-role behaviors decrease. The results also find out that OC has a partial mediating effect between the relationship of OS and OCB which means that with an increase in OC of employees the adverse effect of OS on OCB decreases.