There were 12,059 households out of which 24.5% had children under the age of 18 living with them, 45.9% were married couples living together, 12.5% had a female householder with no husband present, and 37.1% were non-families. 29.7% of all households were made up of individuals and 15.1% had someone living alone who was 65 years of age or older. The average household size was 2.29 and the average family size was 2.80.
In the city the population was spread out with 20.9% under the age of 18, 7.6% from 18 to 24, 28.5% from 25 to 44, 19.4% from 45 to 64, and 23.6% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 87.9 males. For every 100 females age 18 and over, there were 84.2 males.
The median income for a household in the city was $36,941, and the median income for a family was $41,250. Males had a median income of $30,207 versus $25,141 for females. The per capita income for the city was $19,298. About 5.0% of families and 7.2% of the population were below the poverty line, including 8.8% of those under age 18 and 6.5% of those age 65 or over.
As of 2000, speakers of English was the first language of 73.64% of all residents, while Spanish comprised of 21.02%, Italian accounted for 1.69%, French Creole made up 1.09%, German was at 0.71%, and French was the mother tongue for 0.45% of the population.
As of 2000, Greenacres had the ninety-ninth highest percentage of Cuban residents in the US, with 2.41% of the populace (tied with Forest, Mississippi,) while it had the ninety-seventh highest percentage of Colombian residents in the US, at 1.67% of the city's population.