Greenhills is an administrative division in eastern Metro Manila, the Philippines. It is an urban barangay in San Juan and is the largest barangay in the city, covering a total area of 2.09 square kilometers (209 ha) that spans over a third of San Juan's total land area.

San Juan, officially the City of San Juan, is a 1st class highly urbanized city in the National Capital Region of the Philippines. According to the 2020 census, it has a population of 126,347 people. It is geographically located at Metro Manila's approximate center and is also the country's smallest city in terms of land area.