Ōguchi (大口町, Ōguchi-chō) is a town located in Niwa District, Aichi Prefecture, Japan.

Ōguchi is located in the extreme northeast corner of Aichi Prefecture, in the middle of the Nōbi Plain.

Per Japanese census data,[2] the population of Ōguchi has increased steadily over the past 50 years.

[3] The villages of Kashiwamori, Ōta, Ōguchi and Tominari were created within Niwa District, Aichi with the establishment of the modern municipalities system in 1889.

The nearest train station is Kashiwamori on the Meitetsu Inuyama Line in neighboring Fusō.