The current monograph compares the predictions of various dynamic stochastic general equilibrium (DSGE) models with a view to developing an improved understanding of observed fluctuations in small open economies. An analytical framework, synthesising both neoclassical and Keynesian approaches, is proposed resulting in the construction of four different DSGE models, the predictions of which can be tested in the context of any small open economy. For definiteness, the current research focuses exclusively on the two small open economies of UK and Canada. A DSGE model with full price and wage flexibility is initially constructed and then modified through nominal wage and price rigidities. The ability of the models to replicate important features of the business cycle activity in UK and Canada is explored through statistical and econometric analysis. Evidence suggests that a monetary shock under a Taylor model with price stickiness can replicate a significant portion of the business cycle activity in both UK and Canada.