Comcast Corporation (NASDAQ: CMCSA, CMCSK) is the largest cable operator, home Internet service provider, and third largest home telephone service provider in the United States, providing cable television, broadband Internet, telephone service and home security [in some areas] to both residential and commercial customers in 40 states and the District of Columbia.

The company is headquartered in Philadelphia, Pennsylvania. Comcast also has significant holding in several cable networks (including E! Entertainment Television, Style Network, G4, The Golf Channel and NBC Sports Network), distribution (ThePlatform), and related businesses. Comcast acquired a majority stake in media conglomerate NBCUniversal in January 2011. Comcast has been the subject of criticism for activities including its stance on net neutrality, as well as poor results on customer satisfaction surveys.

Comcast Cable was originally formed as American Cable Systems in 1963 and was founded by Ralph J. Roberts, Daniel Aaron, and Julian A. Brodsky based on a recommendation from Pete Musser, who brought the deal to Ralph Roberts to buy his first cable system in Tupelo, Mississippi. The company was incorporated in Pennsylvania in 1969, under the new name Comcast Corporation. The name "Comcast" is a portmanteau of the words "Communication" and "Broadcast".