Western Pennsylvania English, known more narrowly as Pittsburgh English or popularly as Pittsburghese, is a dialect of American English native primarily to the western half of Pennsylvania, centered on the city of Pittsburgh, but potentially appearing in some speakers as far north as Erie County, as far west as Youngstown, Ohio, and as far south as Clarksburg, West Virginia. Commonly associated with the working class of Pittsburgh, users of the dialect are colloquially known as "Yinzers". The dialect is even heard in the town of Hancock, Maryland.

Western Pennsylvania is a region in the Commonwealth of Pennsylvania encompassing the western third of the state. Pittsburgh is the region's principal city, with a metropolitan area population of about 2.4 million people, and serves as its economic and cultural center. Erie, Altoona, and Johnstown are its other metropolitan centers. As of the 2010 census, Western Pennsylvania's total population is nearly 4 million.