We establish conditions under which indeterminacy can occur in a small open economy business cycle model with endogenous labor supply. Indeterminacy requires small externalities in technologies with social constant returns to scale, independently of the intertemporal elasticities in both consumption and labor. Copyright Springer-Verlag Berlin Heidelberg 2003Keywords and Phrases: Indeterminacy, Small open economy, Business cycles., JEL Classification Numbers: E32, F12, F4.,