In 2001, 34% of the population was considered urban, but that is expected to grow, since rural population growth is negative, while overall population growth is still relatively high.

Almost half the population of Comoros is under the age of 15.[54] Major urban centers include Moroni, Mutsamudu, Domoni, Fomboni, and Tsémbéhou. There are between 200,000 and 350,000 Comorians in France.

The islands of the Comoros share mostly African-Arab origins. Malagasy (Christian) and Indian (mostly Ismaili) minorities also exist, as well as minorities mostly descended from early French settlers. Chinese people are also present on Mayotte and parts of Grande Comore (especially Moroni). A small white minority of French with other European (i.e. Dutch, British and Portuguese) ancestry lives in Comoros. Most French left after independence in 1975.

The most common language in Comoros is Comorian, or Shikomor. It is a language related to Swahili, with four different variants (Shingazidja, Shimwali, Shinzwani and Shimaore) being spoken on each of the four islands. Arabic and Latin scripts are both used, Arabic being the more widely used, and an official orthography has recently been developed for the Latin script.

French and Arabic are also official languages, along with Comorian. Arabic is widely known as a second language, being the language of Quranic teaching. French is the administrative language and the language of all non-Quranic formal education. A Malagasy language, Kibushi, is spoken by approximately a third of the population of Mayotte.