This study develops a two-country new Keynesian (NK) model that incorporates deep habits in consumption and investigates the macroeconomic dynamics under the optimal coordinated monetary policy. We show that in response to the structural shocks, the central bank changes the interest rate significantly in the two-country open economy model compared with the closed economy where the central bank is reluctant to move interest rates. When a deep consumption habit exists, the international central bank can exploit the terms of trade externalities. Habit formation might boost the expenditure switching effect, which differentiates the aggressiveness of the central bank between closed and open economies with deep habit. Moreover, we showed that the deviations from the law of one price, or the goods-specific real exchange rate, generated endogenously by the deep habit are significantly related to the degree of home bias. In particular, the deviations fully disappeared when there is no home bias.