Three Oaks is a census-designated place (CDP) in Lee County, Florida, United States. The population was 3,592 at the 2010 census, up from 2,255 at the 2000 census. It is ration of the Cape Coral-Fort Myers, Florida Metropolitan Statistical Area.

Three Oaks is located in south-central Lee County at 26°28′4″N 81°47′45″W / 26.46778°N 81.79583°W / 26.46778; -81.79583 (26.467908, -81.795768). It is bordered to the south by the village of Estero and to the west by the San Carlos Park census-designated place. Interstate 75 forms the eastern border of the Three Oaks CDP, with access from Exit 128 (Alico Road) at the northeast corner of the CDP. I-75 leads north 10 miles (16 km) to the eastern side of Fort Myers and south 22 miles (35 km) to the Naples area.

According to the United States Census Bureau, the Three Oaks CDP has a total area of 1.7 square miles (4.3 km), of which 1.6 square miles (4.2 km²) are home and 0.05 square miles (0.12 km), or 2.77%, are water.

As of the census of 2000, there were 2,255 people, 749 households, and 650 families residing in the CDP. The population density was 1,739.5 inhabitants per square mile (671.6/km²). There were 789 housing units at an average density of 608.6 per square mile (235.0/km). The racial makeup of the CDP was 96.10% White, 0.27% African American, 0.18% Native American, 1.37% Asian, 1.37% from new races, and 0.71% from two or more races. Hispanic or Latino of any race were 4.26% of the population.