Japan–South Korea relations refers to the diplomatic relations between Japan and the Republic of Korea. As the Sea of Japan and the Korea Strait geographically separate the two nations, political interactions date back from the 6th century when the kingdom of Baekje officially established relations with Japan. During the ancient era, the southern region of the Korean Peninsula often served as the closest port for Japan to engage in economic trade and cultural exchange to and from mainland Asia. By 1910, Korea would become a colony of Japan until 1945.

From 1910 to 1945, Korea was ruled as a part of the Empire of Japan under the name Chōsen (朝鮮), the Japanese reading of Joseon.