Buddhism is an Indian, transtheistic religion and philosophy. Around 8.5 million Buddhists live in India, about 0.7% of the total population. Buddhism as a religion is practised mainly in the foothills of the Himalayas and is a significant religion in Sikkim, Arunachal Pradesh, Ladakh, Darjeeling in West Bengal, and the Lahaul and Spiti districts of Himachal Pradesh. Besides, a significant number of Buddhists reside in Maharashtra. They are the Buddhists or Navayana Buddhists who, under the influence of B. R. Ambedkar embraced Buddhism in order to escape the casteist practices within Hinduism. Ambedkar is a crucial figure, along with Anagarika Dharmapala of Sri Lanka and Kripasaran Mahasthavira of Chittagong behind the revival of Buddhism in India in the 19th and 20th centuries. The escape of the 14th Dalai Lama, Tenzing Gyatso to India fleeing Chinese occupation of Tibet in 1959 and the setting up of the Tibetan Government in Exile at Dharamshala in Mcleodganj in Himachal Pradesh has also accelerated the resurgence of Buddhism in India. The effective religion in Sikkim, which joined the Indian Union in 1975 (making it India's 22nd state) remains Vajrayana Buddhism, and Padmasambhava or Guru Ugyen is a revered presence there.

Christianity is a monotheistic religion centred on the life and teachings of Jesus as presented in the New Testament. It is the third largest religion of India, making up 2.3% of the population. St. Thomas is credited with introduction of Christianity in India. He arrived on the Malabar Coast in 52 CE.  The tradition of origin among Saint Thomas Christians relates to the arrival of Saint Thomas, one of the 12 disciples of Jesus at the ancient seaport Muziris on the Kerala coast in 52 CE. The families Sankaramangalam, Pakalomattam, Kalli, and Kaliyankal were considered particularly preeminent, and historically the most aristocratic Syriac Christian families tended to claim descent from these families.

Hinduism is an ancient religion with the largest religious grouping in India, with around 966 million adherents as of 2011, composing 79.8% of the population. Hinduism is diverse, with monotheism, henotheism, polytheism, panentheism, pantheism, monism, atheism, animism, agnosticism, and gnosticism being represented. 

Islam is a monotheistic religion centered on the belief in one God and following the example of Muhammad; it is the largest minority religion in India. About 14.2% of the country's population or approximately 172.2 million people identify as adherents of Islam (2011 census). It makes India the country with the largest Muslim population outside Muslim-majority countries. Muslims are a majority in states Jammu and Kashmir and Lakshadweep, and live in high concentrations in Uttar Pradesh, Bihar, West Bengal, Assam, and Kerala. 

Jainism is a non-theistic Indian religion and philosophical system originating in Iron Age India. Jains compose 0.4% (around 4.45 million) of India's population, and are concentrated in the states of Gujarat, Karnataka, Madhya Pradesh, Maharashtra, and Rajasthan.

Judaism is a monotheistic religion from the Levant. There is today a very small community of Indian Jews. There were more Jews in India historically, including the Cochin Jews of Kerala, the Bene Israel of Maharashtra, and the Baghdadi Jews near Mumbai. Since Indian independence, two primarily proselyte Indian Jewish communities have developed in India: the Bnei Menashe of Mizoram and Manipur, and the Bene Ephraim, also called Telugu Jews. Of the approximately 95,000 Jews of Indian extraction, fewer than 20,000 remain in India. Some parts of India are especially popular with Israelis, swelling local Jewish populations seasonally.

There are several tribal religions in India, such as Donyi-Polo. Santhal is also one of the many tribal religions followed by the Santhal people who number around 4 million but only around 23,645 follow the religion. Bathousim is another tribal religion of Boro community of Assam.

It is difficult to establish the exact numbers of Baháʼís in India. The religion came to India from Iran in about 1850 and gained some converts from the Muslim population of India. The first Sikh and Hindu converts came by 1910, and in 1960 there were fewer than 1,000 Baháʼís in all of India. Beginning in 1961, large numbers from scheduled castes became Baháʼís, and by 1993 Baháʼís reported about 2.2 million members, though later sources have claimed 2 million, or "more than 1 million".

Sanamahism is the indigenous religion of Meitei community in Manipur which they follow along with Vaishnavism.

Parsis (followers of Zoroastrianism in India) represent approximately 0.006% of the total population of India, with relatively high concentrations in and around the city of Mumbai. Parsis number around 61,000 in India.

Sikhism is a monotheistic religion began in fifteenth-century Punjab with the teachings of Guru Nanak and nine successive Sikh gurus. As of 2011, there were 20.8 million Sikhs in India. Punjab is the spiritual home of Sikhs, and is the only state in India where Sikhs form a majority. There are also significant populations of Sikhs in neighbouring Chandigarh, Himachal Pradesh, Jammu division of Jammu and Kashmir, Delhi, and Haryana. These areas were historically a part of Greater Punjab. However, there is no data for specific number of Nanak followers (Nanakpanthis) in India, but they are believed to be in crores somewhere around 14 crores. Karnail Singh Panjoli, member, Shiromani Gurdwara Prabandhak Committee, says that there are several communities within the term ‘Nanakpanthis’ too. “There are groups like Sikhligarh, Vanjaarey, Nirmaley, Lubaney, Johri, Satnamiye, Udaasiyas etc. who call themselves Nanakpanthis. They follow guru Nanak and Sri Guru Granth Sahib.