Kalāheo (literally, "the proud day" in Hawaiian) is an unincorporated community and census-designated place (CDP) in Kauaʻi County, island of Kauaʻi, Hawaiʻi, United States. The population was 4,595 at the 2010 census, up from 3,913 at the 2000 census.
The National Tropical Botanical Garden is located in Kalāheo.
Kalāheo is located on the south side of Kauai at 21°55′28″N 159°31′46″W (21.924430, -159.529358). It is bordered to the east by Lawai. Hawaii Route 50 passes through the community, leading east 12 miles (19 km) to Lihue and west 4 miles (6 km) to Eleele.
According to the United States Census Bureau, the CDP has a total area of 3.6 square miles (9.2 km2), of which 0.04 square miles (0.1 km2), or 1.23%, are water.
As of the census of 2000, there were 3,913 people, 1,428 households, and 1,039 families living in the CDP. The population density was 1,328.5 people per square mile (512.1/km2). There were 1,509 housing units at an average density of 512.3 per square mile (197.5/km2). The racial makeup of the CDP was 40.0% White, 0.2% African American, 0.2% Native American, 29.6% Asian, 3.9% Pacific Islander, 1.2% from other races, and 24.9% from two or more races. Hispanic or Latino of any race were 11.5% of the population.