There were 10,107 households out of which 43.7% had children under the age of 18 living with them, 68.5% were married couples living together, 8.7% had a female householder with no husband present, and 20.0% were non-families. 17.0% of all households were made up of individuals and 6.3% had someone living alone who was 65 years of age or older. The average household size was 2.85 and the average family size was 3.23.
In the city the population was spread out with 30.0% under the age of 18, 6.2% from 18 to 24, 29.4% from 25 to 44, 25.7% from 45 to 64, and 8.6% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 93.7 males. For every 100 females age 18 and over, there were 90.4 males.
According to a 2006 estimate, the median income for a family in Friendswood was $90,232. Males had a median income of $60,304 versus $35,447 for females. The per capita income for the city was $28,615. About 2.3% of families and 3.3% of the population were below the poverty line, including 3.4% of those under age 18 and 3.8% of those age 65 or over.
Cline Elementary School, Westwood Elementary School, Bales Intermediate School, and Windsong Intermediate School serve the Friendswood ISD portion of Friendswood. All Friendswood ISD residents are zoned to Friendswood Junior High School and Friendswood High School.
Clear Creek ISD students from Friendswood, depending on attendance boundary, attend either Wedgewood Elementary School in Friendswood or Landolt Elementary School for elementary school. Most CCISD areas of Friendswood are zoned to Brookside Intermediate School in Friendswood. One section of land is zoned to Westbrook Intermediate School in Houston. Depending on attendance boundary, some students continue to Clear Brook High School in an unincorporated area of Harris County adjacent to Friendswood, while some students continue to Clear Springs High School in League City.