As of the census of 2000, there were 13,164 people, 4,349 households, and 3,566 families residing in the town. The population density was 843.4 people per square mile (325.6/km²). There were 4,445 housing units at an average density of 284.8/sq mi (109.9/km²). The racial makeup of the town was 97.68% White, 0.55% African American, 0.08% Native American, 0.77% Asian, 0.01% Pacific Islander, 0.27% from other races, and 0.65% from two or more races. Hispanic or Latino of any race were 0.68% of the population]].
There were 4,350 households out of which 43.8% had children under the age of 18 living with them, 70.8% were married couples living together, 8.0% had a female householder with no husband present, and 18.0% were non-families. 15.2% of all households were made up of individuals and 8.8% have someone living alone who is 65 years of age or older. The average household size was 3.02 and the average family size was 3.39.
In the town the population was spread out with 29.8% under the age of 18, 5.6% from 18 to 24, 28.8% from 25 to 44, 25.3% from 45 to 64, and 10.5% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 95.9 males. For every 100 females age 18 and over, there were 91.3 males.
The median income for a household in the town was $73,838, and the median income for a family was $86,835. Males had a median income of $57,321 versus $35,214 for females. The per capita income for the town was $30,268. About 1.4% of families and 2.3% of the population were below the poverty line, including 1.6% of those under age 18 and 7.8% of those age 65 or over.
A short, 1-1/4 mile portion of Massachusetts Route 3, a four-lane freeway, passes through the town, providing access via an exit at Route 53 in the northeast corner of town. The town's other major routes include Route 123 and Route 139, the latter passing through the town center. Routes 139 and 53 are coextensive for a stretch of one mile in the southeast corner of town.
The town has no rail or air service. The nearest rail service is the Kingston-Route 3 line of the MBTA's commuter rail service, which passes west of town, the closest stations being in Abington and Hanson. The nearest regional airport is Marshfield Municipal Airport, and the nearest national and international service can be reached at Logan International Airport in Boston. Seaplanes also occasionally land in neighboring Hanson, on Lake Monponsett.