The Research Triangle, commonly referred to as simply "The Triangle", is a region in the Piedmont of North Carolina in the United States, anchored by North Carolina State University, Duke University, University of North Carolina at Chapel Hill, and the cities of Raleigh and Durham and the towns of Cary and Chapel Hill. The eight-county region, officially named the Raleigh–Durham–Chapel Hill CSA, comprises the Raleigh and Durham–Chapel Hill metropolitan areas.  A 2013 Census estimate put the population at 2,037,430.

The "Triangle" name was cemented in the public consciousness in the 1950s with the creation of Research Triangle Park, home to numerous high-tech companies and enterprises. Although the name is now used to refer to the geographic region, "the Triangle" originally referred to the universities, whose research facilities, and the educated workforce they provide, have historically served as a major attraction for businesses located in the region. The region should not be confused with "The Triad", which is a North Carolina region adjacent to and directly west of the Triangle comprising Greensboro, Winston-Salem, and High Point, among other cities. Most of the Triangle is represented by, and closely associated with, the second, fourth, and 13th congressional districts. The Raleigh–Durham–Chapel Hill Combined Statistical Area consists of 5,627 square miles (land and water).

The Triangle region, as defined for statistical purposes as the Raleigh–Durham–Cary CSA, comprises eight counties, although the U.S. Census Bureau divided the region into two metropolitan statistical areas and one micropolitan area in 2003. The Raleigh-Cary metropolitan area comprises Wake, Franklin, and Johnston Counties; the Durham-Chapel Hill metropolitan area comprises Durham, Orange, Chatham, and Person Counties; and the Dunn micropolitan area comprises Harnett County. However, for all intents and purposes it still functions as a single metropolitan area. Some area television stations define the region as Raleigh–Durham–Fayetteville. Fayetteville, North Carolina, is over 50 miles (80 km) from Raleigh, but is part of the Triangle television market.