The Toi invasion (Japanese:刀伊の入寇 toi no nyūkō) was the invasion of northern Kyushu by Jurchen pirates in 1019. Toi (되, doe) means barbarian in Korean.

Sailing in about 50 ships from direction of Goryeo, the Toi pirates assaulted Iki, Tsushima and then Hakata Bay . Using Noko Island (能古島 noko no shima) in the bay as the base, they despoiled villages and kidnapped Japanese people for use as slaves for a week. At that time, Fujiwara no Takaie served as the head of Dazaifu, the administrative center of Kyushu. He braced soldiers and successfully drove them away.

Some enemies were captured by Japanese army in Matsura, but all of them were identified as Koreans. They said that they had guarded the borderland but had been captured by the Toi. However, Japanese officers suspected them because there had been a lot of Korean pirates in the Silla period. A few months later, the Goryeo delegate Jeong Jaryang (鄭子良) reported that Goryeo attacked the pirates in the offing of Wŏnsan and rescued about 260 Japanese. There remain detailed reports by two captive women, Kura no Iwame and Tajihi no Akomi.

These Jurchen pirates lived in what is today Hamgyŏngdo, North Korea. They frequently attacked the eastern coast of the Korean peninsula. In particular, Ulleungdo became uninhabited because of their massive attacks. The invasion in 1019 was one of those incidents.