Since the period of military government, Nigeria has been witnessing series of security challenges. However, when the country return to civilian government in 1999 the issue of insecurity became worsened. This paper examines the effect of insecurity on economic growth in Nigeria. Secondary sources were used as data for this work. The findings revealed that insecurity affects economic growth by driven away both foreign and local investors and discourage the intending ones, increases unemployment, fall in government revenue among others. The study therefore recommends that the leadership should be more sincere, effective and transparent enough while discharging their duties. In conclusion, the government should formulate appropriate policies and designed other strategies that will eliminate the problem of insecurity in Nigeria