In this paper, we study the relationship between pollution and military expenditure. A distinction is drawn between the indirect and direct impact of military expenditure on pollution which operates through the impact of military expenditure on income and the resultant impact of income on pollution. Using data of 120 countries covering the period 1980–2015, both indirect and direct effects of military expenditure on air pollution emissions are estimated. The results show that the military expenditure is estimated to have a positive direct effect on per capita emissions. Indirect effect is found to be positive, the total effect of military expenditure on emissions is positive.