Lake Worth Beach, previously named Lake Worth, is a city in east-central Palm Beach County, Florida, United States, located about 64 miles (103 km) north of Miami. The city's name is derived from the body of water along its eastern border known as the Lake Worth Lagoon, which was named for General William J. Worth, who led United States Army forces during the last part of the Second Seminole War. Lake Worth Beach is situated south of West Palm Beach, southeast of Lake Clarke Shores, east of Palm Springs, and north of Lantana, while a small section of the city also partitions the town of Palm Beach. The 2010 census recorded a population of 34,910, which increased to 42,219 in the 2020 census. Lake Worth Beach is within the Miami metropolitan area, which was home to an estimated 6,138,333 people in 2020.

William Jenkins Worth was an American officer during the War of 1812, the Second Seminole War, and the Mexican–American War.