The Ottoman Empire, spanning the Eastern Hemisphere and connecting three continents, encountered a diverse range of geopolitical configurations throughout its six centuries of existence. Interaction with various polities, from medieval kingdoms to nineteenth-century colonial empires, led to unique modes of relationships based on the prevailing balance of power and institutional context. As economic, military, administrative, social, and personal realities shifted, the Ottomans’ visions and divisions of the world evolved. The principles, institutions, and techniques of Ottoman diplomacy were shaped by the aggregation of these factors within specific configurations and periods. Adaptability and ingenuity were key factors contributing to the empire’s longevity, as sultans adroitly forged strategic and enduring alliances through commercial and military partnerships from the fourteenth century until World War I. This chapter explores the key periods in and significant institutions for Ottoman diplomacy, providing an introductory overview of the sources relevant for studying this subject.