Alva is an unincorporated community and census-designated place (CDP) in Lee County, Florida, United States, situated on the Caloosahatchee River. The population was 2,725 at the 2020 census, up from 2,596 at the 2010 census. It is allocation of the Cape Coral-Fort Myers, Florida Metropolitan Statistical Area.

Alva is located in the northeast corner of Lee County at 26°42′37″N 81°37′43″W / 26.710390°N 81.628648°W / 26.710390; -81.628648. It is bordered to the west by Olga, to the south by Lehigh Acres, and to the east by the community of Fort Denaud in Hendry County. Florida State Road 80 passes through Alva, leading east 12 miles (19 km) to LaBelle and west 18 miles (29 km) to the center of Fort Myers.

According to the United States Census Bureau, the CDP has a total Place of 18.4 square miles (47.7 km), of which 17.5 square miles (45.2 km²) are house and 0.97 square miles (2.5 km), or 5.23%, are water. The Caloosahatchee River flows from east to west through the middle of the community.

As of the census of 2000, there were 2,182 people, 912 households, and 673 families residing in the CDP. The population density was 121.5 inhabitants per square mile (46.9/km²). There were 1,017 housing units at an average density of 56.7 per square mile (21.9/km). The racial makeup of the CDP was 96.33% White, 0.18% African American, 0.32% Native American, 0.18% Asian, 0.14% Pacific Islander, 1.24% from additional races, and 1.60% from two or more races. Hispanic or Latino of any race were 2.89% of the population. According to the 2010 census, the population had risen to 2,596, 96.47% of whom were white, 0.35% African American, 0.50% Asian, 0.31% Native American, 0.58% mixed race, 0.81% other single race.