Fujikawaguchiko (富士河口湖町, Fujikawaguchiko-machi) is a town located in Yamanashi Prefecture, Japan. As of 1 June 2019, the town had an estimated population of 26,542 in 10618 households, and a population density of 170 persons per km2. The total area of the town is 158.40 square kilometres (61.16 sq mi).
The area around Lake Kawaguchi has been inhabited since at least the Jōmon period. It was on the road connecting Kai Province with Suruga Province, and is mentioned in Heian period records, which also document an eruption of Mount Fuji in 864 AD. During the Edo period, all of Kai Province was tenryō territory under direct control of the Tokugawa shogunate. During the cadastral reform of the early Meiji period on July 1, 1889, the area came under the jurisdiction of Minamitsuru District, Yamanashi Prefecture.
On 15 November 2003, the town of Kawaguchiko, and the villages of Katsuyama and Ashiwada merged to form the new town of Fujikawaguchiko. The headquarters of the infamous Aum Shinrikyo was located in the village of Kamikuishiki, most of which was absorbed into Fujikawaguchiko on 1 March 2006.