Gamagōri (蒲郡市, Gamagōri-shi) is a city in Aichi Prefecture, Japan.
As of 1 October 2019, the city had an estimated population of 80,063 in 32,800 households, and a population density of 1,407 persons per km². The total area of the city is 56.92 square kilometres (21.98 sq mi).
Gamagōri is situated on the coast of Mikawa Bay on the Pacific Ocean in southeastern Aichi Prefecture. Sheltered by Chita Peninsula and Atsumi Peninsula, the climate is mild, and parts of the city is within the borders of the Mikawa Wan Quasi-National Park.