This paper tests the prediction that more open economies experience lower average inflation due to the reduced incentives for monetary expansion. The theory suggests that unanticipated monetary expansion leads to real exchange rate depreciation, which is more harmful in open economies. Models without precommitment in monetary policy predict lower inflation in more open economies. Cross-country data show a strong negative relationship between openness and inflation, confirming the theory. The results are robust to various controls, including political stability and central bank independence. The relationship holds across most countries except for the most developed ones, which have largely overcome the dynamic inconsistency problem in monetary policy. Alternative explanations, such as endogenous openness and budgetary considerations, are inconsistent with the data. The findings suggest that models of monetary policy without precommitment are essential for understanding inflation, and that increased economic integration without mechanisms to address dynamic inconsistency could lead to higher inflation. The paper concludes that more open economies have lower inflation due to reduced incentives for expansion, and that the most developed countries have found ways to overcome the dynamic inconsistency problem.This paper tests the prediction that more open economies experience lower average inflation due to the reduced incentives for monetary expansion. The theory suggests that unanticipated monetary expansion leads to real exchange rate depreciation, which is more harmful in open economies. Models without precommitment in monetary policy predict lower inflation in more open economies. Cross-country data show a strong negative relationship between openness and inflation, confirming the theory. The results are robust to various controls, including political stability and central bank independence. The relationship holds across most countries except for the most developed ones, which have largely overcome the dynamic inconsistency problem in monetary policy. Alternative explanations, such as endogenous openness and budgetary considerations, are inconsistent with the data. The findings suggest that models of monetary policy without precommitment are essential for understanding inflation, and that increased economic integration without mechanisms to address dynamic inconsistency could lead to higher inflation. The paper concludes that more open economies have lower inflation due to reduced incentives for expansion, and that the most developed countries have found ways to overcome the dynamic inconsistency problem.