We analyze the implications of openness and growth for determinacy and learnability of rational expectations equilibria in a two-country New Keynesian model with alternative monetary policy rules. Under the contemporaneous data rule, the conditions for determinacy and learnability become more stringent as a result of openness but less stringent as a result of growth, so that growth weakens the effect of openness. Under the expectations-based rule, the conditions for determinacy and learnability also become more stringent as a result of openness, whereas as a result of trend growth the conditions for determinacy also become more stringent (thus reinforcing the effect of openness) but those for learnability become less stringent (thus weakening the effect of openness). As in related studies, the elasticity of intertemporal substitution is key to our result, but within a framework that is consistent with long-run labor supply and balanced growth facts.