In terms of college education, Joliet is somewhat better educated than the 21.84% who have a 4-year degree or higher in the typical US community: 25.03% of adults 25 and older in the city have at least a bachelor's degree.

The per capita income in Joliet in 2022 was $35,820, which is middle income relative to Illinois and the nation. This equates to an annual income of $143,280 for a family of four. However, Joliet contains both very wealthy and poor people as well.

Joliet is an extremely ethnically-diverse city. The people who call Joliet home describe themselves as belonging to a variety of racial and ethnic groups. The greatest number of Joliet residents report their race to be White, followed by Black or African-American. Joliet also has a sizeable Hispanic population (people of Hispanic origin can be of any race). People of Hispanic or Latino origin account for 34.70% of the city鈥檚 residents. Important ancestries of people in Joliet include German, Irish, Polish, Italian, and English.

Joliet also has a high percentage of its population that was born in another country: 15.20%.

The most common language spoken in Joliet is English. Other important languages spoken here include Spanish and Polish.