This book empirically test the existence of Phillips curve and shed light on dynamics of inflation in developing countries using Nigeria and Sri Lanka as the case study. Inflation and Unemployment are perhaps the two most important macroeconomic challenges that developing countries face today and one of the most important economic theories that link these two macroeconomic variables is Phillips curve. This book utilized theoretical and empirical approaches with the help of derived baseline model that almost similar to the model of Fumitaka (2007)to test for the existence or otherwise of Traditional Phillips curve and the Expectation-Augmented Phillips curve in Nigeria and Sri Lanka. With the proper adoption of Classical Linear Regression Model,OLS,VAR and ECM, the book test for the existence of Phillips curve and determine the determinants of inflation in the two countries. Attempt was made to see the impact of both supply side and demand side of the economy as well as election period on inflation. The book also brings out the stylized fact about inflation and other macroeconomic variables in Nigeria and Sri Lanka.