Diplomatic history is a subfield of history that focuses on the interactions and relationships between states and their representatives. It is concerned with the nature of diplomacy and the role it plays in shaping international relations. Diplomatic history also encompasses a wide range of areas including the study of treaties, alliances, war and peace, and the role of diplomacy in shaping the modern world. More so, the discipline looks at the influence of non-state actors, such as individuals, corporations, and NGOs, on the course of diplomatic history. In addition, the scope of diplomatic history is vast and covers a range of historical periods and regions. The field also studies the impact of culture, emotions, and identity on diplomatic interactions. However, the discipline is faced by some challenges and limitations. Some historians argue that diplomatic history is too focused on state actors and official sources, and that it fails to account for the experiences of ordinary people. This paper examines the nature and scope of diplomatic history. It explains the meaning of history, diplomacy and how the concept of diplomatic history evolved and the role of diplomacy in history. It also highlighted the impact of diplomacy on world events. The relationship between diplomatic history and other disciplines was also examined. The paper uses a historical research approach in its analysis.