This paper investigates firm values and investment strategies (investment, coupon, and default timing) when several firms make strategic real investments with debt financing. We derive and compare the equilibrium investment strategies in three types of duopolies: (i) two symmetric firms, both of which can issue debt, (ii) two symmetric firms, only one of which (the leader) can issue debt, and (iii) a levered firm versus an unlevered firm. We show that in (iii) and in equilibrium, the levered firm always invests prior to the unlevered firm. Further, we derive the equilibrium in a oligopoly of n levered firms, and show that social loss increases as the number of the firms, n, becomes larger.