This article investigates how strategic culture influenced the decision-making of Australia and Poland regarding the global coalition against the Islamic State. In the coalition, Australia has followed its tradition of active participation in United States-led operations, while Poland has embarked on a more cautious line, thereby breaking with its previous policy of active participation. The article examines how Australian and Polish responses to the coalition were shaped by five cultural elements: dominant threat perception, core task of the armed forces, strategic partners, experiences of participating in coalitions of the willing, and approach to the international legality of expeditionary operations. It finds that Australia and Poland differed on all five elements but that the major differences are found in dominant threat perception and core task of the armed forces.