As of 2005 Bangalore had a population of over six million, making it the 3rd most populous city in India and the 27th largest city in the world by population. With a decadal growth rate of 38%, Bangalore was the fastest-growing Indian metropolis after New Delhi for the decade 1991–2001.

Residents of Bangalore are referred to as Bangaloreans. While Kannadigas accounted for 38% of the population, sizable minorities from Tamil Nadu, Kerala, Andhra Pradesh and Maharashtra exist. Scheduled Castes and Tribes account for 14.3% of the city's population. Kannada, the official language of the state of Karnataka, is widely spoken in Bangalore, as are Tamil, Telugu,Tulu and Hindi. English is the lingua franca of the city's white-collar workforce.

According to the 2001 census of India, 79.37% of Bangalore's population is Hindu — roughly the same as the national average. Muslims comprise 13.37% of the population, which again is roughly the same as the national average, while Christians and Jains account for 5.79% and 1.05% of the population, respectively, double that of their national averages.

Women make up 47.5% of Bangalore's population. Bangalore has the second highest literacy rate (83%) for an Indian metropolis, after Mumbai. The city's workforce structure is predominantly non-agrarian, with only 6% of Bangalore's workforce being engaged in agriculture-related activities. Roughly 10% of Bangalore's population lives in slums[40] — a relatively low proportion when compared to other cities in the developing world such as Mumbai (54%) and Nairobi (60%).

The 2004 National Crime Records Bureau statistics indicate that Bangalore accounts for 9.2% of the total crimes reported from 35 major cities in India. Delhi and Mumbai accounted for 15.7% and 9.5% respectively. Communal tensions between the city's two largest ethnic groups, the Kannadigas and the Tamils, have led to numerous altercations.

In early 1991, tensions between the two groups flared up with the proposed installation of a statue honouring the Tamil poet Thiruvalluvar in the city. Widespread agitation and protests organised by groups sympathetic to Kannadigas led the Commissioner of the Bangalore City Corporation to withdraw permission to unveil the statue, which remains wrapped under cloth.

Later the same year, the Karnataka Government, acting upon the directives of the Government of India, agreed to release 205 tmc of water from the river Kaveri to the Government of Tamil Nadu, which resulted in anti-Tamil riots that left 20 people dead.

After the demolition of the Babri Masjid in the North Indian city of Ayodhya in 1992, communal violence between Hindus and Muslims spread to Bangalore during which Muslim houses and huts as well as an Arabic school for Muslim girls were raided and torched. In 1997 the demolition of a stone structure in a mosque in Jayanagar led to violence in sensitive areas in the city that left four dead.