North Liberty is a city in Johnson County, Iowa, United States. It is a suburb of Iowa City and part of the Iowa City Metropolitan Statistical Area. As of the 2020 census, the city population was 20,479. From 2000 to 2010, North Liberty was the second fastest-growing city in Iowa. A 2017 LendEDU poll named North Liberty the ninth most educated city in the United States and the most educated city in the Midwest.