The Lake Pontchartrain Causeway (French: Chaussée du lac Pontchartrain), also known simply as The Causeway, is a fixed link composed of two parallel bridges crossing Lake Pontchartrain in southeastern Louisiana, United States. The longer of the two bridges is 23.83 miles (38.35 km) long. The southern terminus of the causeway is in Metairie, Louisiana, and the northern terminus is in Mandeville, Louisiana. Both are in the New Orleans metropolitan area.

The Lake Pontchartrain Causeway holds the Guinness World Record for longest continuous span over water in the world. It previously was listed as longest bridge over water in the world; in 2011, in response to the opening of the Qingdao Jiaozhou Bay Bridge in China, Guinness World Records created two categories for bridges over water: Lake Pontchartrain Causeway then became the longest bridge over water (continuous), while the Jiaozhou Bay Bridge became the longest bridge over water (aggregate).

The bridges are supported by 9,500 concrete pilings. The two bridges feature a bascule, which spans the navigation channel 8 miles (13 km) south of the north shore.