Lanagan is a city in McDonald County, Missouri, United States.

Missouri Route 59 passes through the town as Main Street, leading north 3 miles (5 km) to Anderson and south 6 miles (10 km) to Noel.

According to the U.S. Census Bureau, Lanagan has a total area of 0.94 square miles (2.43 km2), all of it recorded as land.

33.3% of all households were made up of individuals, and 16.4% had someone living alone who was 65 years of age or older.

34.7% of all households were made up of individuals, and 21.8% had someone living alone who was 65 years of age or older.

Lanagan’s economy has traditionally relied on agriculture, small-scale manufacturing, and retail businesses.

In recent years, tourism has grown due to its proximity to natural attractions like Truitt's Cave.

However, like many small towns, Lanagan faces economic challenges, with a median household income of $40,625 and a significant portion (19.9%) of the population living below the poverty line.