The Invasion of Shikoku was a conflict of the Sengoku period of Japan fought between Toyotomi Hideyoshi and Chōsokabe Motochika on the island of Shikoku in 1585. Hideyoshi invaded Shikoku with a force of over 100,000 men in June and led a campaign against the Chōsokabe clan force of 40,000 men for control over the island. Hideyoshi's army was successful and conquered most of Shikoku within two months, and defeated Chōsokabe when he surrendered Ichinomiya Castle in August.

The Sengoku period, also known as Sengoku Jidai is the period in Japanese history in which civil wars and social upheavals took place almost continuously in the 15th and 16th centuries. Although the Kyōtoku incident (1454), Ōnin War (1467) or Meiō incident (1493) are generally chosen as the Sengoku period's start date, there are many competing historiographies for its end date, ranging from 1568, the date of Oda Nobunaga's march on Kyoto, to the suppression of the Shimabara Rebellion in 1638, deep into what is traditionally considered the Edo period. Regardless of the dates chosen, the Sengoku period overlaps substantially with the Muromachi period (1336–1573).