Azerbaijan is more populated than other Transcaucasian states, Georgia and Armenia. Its population was an estimated 9,022,000 in 2010, giving it an average density of 90 persons per sq. km. The most densely populated area is the Absheron Peninsula in the east, where Azerbaijan’s major cities are located. Despite its larger population, Azerbaijan is the least urbanized country of Transcaucasia. The biggest city is Baku, the capital. Other important cities include Ganja, the industrial center of western Azerbaijan, and Sumgait, located on the Caspian coast, the second most important industrial center after Baku. The urban population makes up 55.8% and the rural population 44.2% of the population, respectively. The average life expectancy is 72 years.

Mostly ethnic Azerbaijanis populate Azerbaijan, including the autonomous exclave of Nakhchivan. The Azerbaijani majority has increased dramatically as a result of recent population shifts. By the mid-1990s the proportion of Azerbaijanis in the republic had reached about 90% of the total population, an increase of nearly 10% since the 1989 census. Today Dagestanis (Lezgin) and Russians are the largest minority followed by Armenians. In the mid-1990s Dagestanis (Lezgin) represented an estimated 3.2%, Russians constituted 2.5% and Armenians constituted 2% of the population. Other ethnic groups, which make up the remaining 2.3%, include Kurds and Talysh. These peoples are geographically concentrated in the west and south of the republic. There are also small communities of Georgians, Ukrainians, Avars and Jewish.

Azerbaijanis are traditionally Muslim. But the first religion in Azerbaijan was Zoroastrianism. The official religion, Zoroastrianism, was based on fire worship, the spread of which was propagated by the spontaneous ignition of shallow oil deposits and escaping gas. Christianity started to be introduced in Caucasus and Azerbaijan at the beginning of the Common Era. Christianity in Albania covered two stages, Apostolic (1st to 3rd century) and Greekophil (4th to 6th century). The Albanian Apostolic Church is the most ancient church in the Caucasus and one of the earliest in Christianity. The Albanians residing in the mountainous Karabakh region retained their Christianity until 1836, when the Russian authorities, on the instigation by the Armenian Church, abolished the Albanian patriarchate. Islam was introduced to the area of present-day Azerbaijan during 7th century AD and Shite Islam was established as the official religion of Azerbaijan in the 16th century. During the Soviet period, religious observance was officially forbidden. Islam has experienced a revival in Azerbaijan since the late 1980s, when political reforms allowed most of the Soviet restrictions on religion to be lifted. Nearly all Azerbaijanis now identify themselves as Muslim, although few actively practice their religion. Christianity is practiced to varying degrees among the Armenian and Slavic. There is also a Jewish minority in the country.

The Azerbaijani language is a part of the Oguz family of Turkic languages. Today 88% of the population speaks Azerbaijani, 3% have Russian as their mother tongue, 2% speak Armenian and the remaining 6% speak other languages. The Azerbaijani language is written in Latin script, which replaced the Cyrillic script in 1992. State decrees are published in Azerbaijani, English and Russian.

Education in Azerbaijan is secular and widespread – the population has a 97% literacy rate. The country’s high adult literacy rate was achieved during the Soviet period, when an extensive state-funded education system was developed. The state guarantees free compulsory secondary education to all citizens, and also provides free education on the university-level for those wishing to pursue a higher degree. Baku is the seat of most of the country’s institutes of higher degree and the seat of most of the country’s institutes of higher education, including Baku State University (founded in 1919 during Azerbaijan’s brief initial period of independence), Azerbaijan State Petroleum Academy (founded in 1920) and Azerbaijan Technical University (founded in 1950). The average education is eleven years for both males and females. There has been an increase in high school education over the past five years, but a slight decline in technical and university graduations.