Guaynabo is a city and municipality situated on the northeastern coastal plain of Puerto Rico. It is part of the San Juan metropolitan area and is positioned west of the capital, San Juan; east of Bayamón; south of Cataño and San Juan Bay; and north of Aguas Buenas.
The municipality covers a land area of 27.13 square miles (70.3 km2) and is divided into nine barrios along with the downtown administrative center known as Guaynabo Pueblo. As of the 2020 census, the city had a population of 89,780.
Guaynabo is notable for housing the studios of WAPA-TV, which is recognized as the most watched television station in Puerto Rico.