As of the United States 2000 Census, there were 33,556 people, 10,846 households, and 8,633 families residing in the city. The population density was 2,875.4 people per square mile (1,110.2/km²). There were 11,091 housing units at an average density of 950.3/sq mi (366.9/km²). The racial makeup of the city was 72.40% White, 1.71% African American, 1.08% Native American, 6.02% Asian, 0.23% Pacific Islander, 13.43% from other races, and 5.13% from two or more races. Hispanic or Latino of any race were 27.50% of the population.
There were 10,846 households out of which 44.0% had children under the age of 18 living with them, 63.2% were married couples living together, 11.1% had a female householder with no husband present, and 20.4% were non-families. 15.1% of all households were made up of individuals and 5.5% had someone living alone who was 65 years of age or older. The average household size was 3.05 and the average family size was 3.38.
In the city the population was spread out with 30.5% under the age of 18, 7.6% from 18 to 24, 31.7% from 25 to 44, 22.7% from 45 to 64, and 7.5% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 98.5 males. For every 100 females age 18 and over, there were 94.9 males.
According to a 2007 estimate, the median income for a household in the city was $99,243, and the median income for a family was $108,611. Males had a median income of $61,999 versus $42,003 for females. The per capita income for the city was $33,047. About 3.3% of families and 4.7% of the population were below the poverty line, including 5.4% of those under age 18 and 4.9% of those age 65 or over.
Substantial expansion of the population of Morgan Hill occurred from the late 1980s onward. This population expansion was enabled by the removal of a growth constraint in the form of sewage treatment capacity.
Pacific Gas and Electric Company (PG&E) provides gas and electricity for the city. Water and sewer services are provided by the City of Morgan Hill. Household waste disposal and recycling are provided by South Valley Disposal & Recycling, Inc.
Morgan Hill has four sister cities, as designated by Sister Cities International: