Heterogeneous expectations can be a challenge for macroeconomic policy. In a Neo-Classical economy, different policy arrangements are needed to stabilize the economy when agents have rational or adaptive expectations. A monetary policy rule with expectational heterogeneity can lead to a unique and stable solution under a passive fiscal/active monetary policy regime. However, an active fiscal/passive monetary policy regime may face instability due to expectational heterogeneity. Operational monetary policy rules mainly favor the fiscalist solution. These findings are relevant for understanding business cycle dynamics and can be explained from an adaptive learning perspective.