Ngee Ann Secondary School (NASS) is a co-educational government-aided autonomous secondary school in Tampines, Singapore. Founded in 1994 by the Ngee Ann Kongsi, a Teochew clan foundation, Ngee Ann Secondary School is a successor to the now defunct Tuan Mong High School. The school offers secondary education leading to the Singapore-Cambridge GCE Ordinary Level or Singapore-Cambridge GCE Normal Level examination.

Tampines is the regional centre of the East Region of Singapore. With a population of 274,360 living across its five subzones, it is the second-most populous planning area in Singapore, according to the DOS Population Trends 2023. It is home to approximately 5% of Singapore's population. Tampines is bordered to the west by Bedok and Paya Lebar, to the north by Pasir Ris, to the east by Changi, and to the south by the Straits of Singapore. Situated in the historical region of Tanah Merah, its present-day terrain is particularly flat due to the large-scale sand quarrying in the 1960s.