Santa Monica's population has grown from 417 in 1880 to 84,084 in 2000. For population statistics by decade, see History of Santa Monica, California.

As of the census of 2000, there are 84,084 people, 44,497 households, and 16,775 families in the city. The population density is 3,930.4/km˛ (10,178.7/mi˛). There are 47,863 housing units at an average density of 2,237.3/km˛ (5,794.0/mi˛). The racial makeup of the city is 78.29% White, 7.25% Asian, 3.78% African American, 0.47% Native American, 0.10% Pacific Islander, 5.97% from other races, and 4.13% from two or more races. 13.44% of the population are Hispanic or Latino of any race. There are 44,497 households, out of which 15.8% have children under the age of 18, 27.5% are married couples living together, 7.5% have a female householder with no husband present, and 62.3% are non-families. 51.2% of all households are made up of individuals and 10.6% have someone living alone who is 65 years of age or older. The average household size is 1.83 and the average family size is 2.80.

The population is diverse in age, with 14.6% under 18, 6.1% from 18 to 24, 40.1% from 25 to 44, 24.8% from 45 to 64, and 14.4% 65 years or older. The median age is 39 years. For every 100 females there are 93.0 males. For every 100 females age 18 and over, there are 91.3 males. The median income for a household in the city is $50,714, and the median income for a family is $75,989. Males have a median income of $55,689 versus $42,948 for females. The per capita income for the city is $42,874. 10.4% of the population and 5.4% of families are below the poverty line. Out of the total population, 9.9% of those under the age of 18 and 10.2% of those 65 and older are living below the poverty line.