Guaynabo is a city, suburb of San Juan and municipality in the northern part of Puerto Rico, located in the northern coast of the island, north of Aguas Buenas, south of Cataño, east of Bayamón, and west of San Juan. Guaynabo is spread over 9 barrios and Guaynabo Pueblo. Guaynabo is considered, along with its neighbors – San Juan and the municipalities of Bayamón, Carolina, Cataño, Trujillo Alto, and Toa Baja – to be part of the San Juan metropolitan area. It is also part of the larger San Juan-Caguas-Guaynabo Metropolitan Statistical Area,.

The San Juan metropolitan area is a United States Census Bureau defined metropolitan statistical area (MSA) in northeastern Puerto Rico centered around the city of San Juan. A July 1, 2009, Census Bureau estimate placed the population at 2,617,089, a 4.31% increase over the 2000 census figure of 2,509,007.