Hinduism is the most widely professed faith in Kerala. According to 2011 Census of India figures, 54.7% of Kerala's residents are Hindus. Hindus represent the biggest religious group in all districts except Malappuram.

Adi Shankara, was from Kerala.

Kerala produced several saints and movements. Adi Shankara was a religious philosopher who contributed to Hinduism and propagated the philosophy of Advaita. He was instrumental in establishing four mathas at Sringeri, Dwarka, Puri and Jyotirmath. Melpathur Narayana Bhattathiri was another religious figure who composed Narayaniyam, a collection of verses in praise of the Hindu God Krishna.

Various practises of Hinduism are unique to Kerala. Worship of Shiva and Vishnu is popular in Kerala. Lord Krishna is worshipped widely in all parts of Kerala, Guruvayur being one of the most famous temples in the state. Malayali Hindus also worship Bhagavathi as a form of Shakti. Almost every village in Kerala has a Bhagavati Goddess. Hindus in Kerala also strongly believe in power of snake gods and usually have sacred snake groves known as Sarpa Kavu near to their houses.Kerala has been a major spice exporter since 3000 BCE, according to Sumerian records and it is still referred to as the "Garden of Spices" or as the "Spice Garden of India".: 79  Kerala's spices attracted ancient Arabs, Babylonians, Assyrians and Egyptians to the Malabar Coast in the 3rd and 2nd millennia BCE. Phoenicians established trade with Kerala during this period. Arabs and Phoenicians were the first to enter Malabar Coast to trade Spices. The Arabs on the coasts of Yemen, Oman, and the Persian Gulf, must have made the first long voyage to Kerala and other eastern countries. They must have brought the Cinnamon of Kerala to the Middle East. The Greek historian Herodotus (5th century BCE) records that in his time the cinnamon spice industry was monopolized by the Egyptians and the Phoenicians.

Islam arrived in Kerala, a part of the larger Indian Ocean rim, via spice and silk traders from the Middle East. Historians do not rule out the possibility of Islam being introduced to Kerala as early as the seventh century CE. Northern Kerala Muslims are generally referred to as the Mappilas. Mappilas are but one among the many communities that forms the Muslim population of Northern Kerala. The first Indian mosque was built in 624 AD at Kodungallur. According to Qissat Shakarwati Farmad, the Masjids at Kodungallur, Kollam, Madayi, Barkur, Mangalore, Kasaragod, Kannur, Dharmadam, Panthalayini, and Chaliyam, were built during the era of Malik Dinar, and they are among the oldest Masjids in the Indian subcontinent. It is believed that Malik Dinar died at Thalangara in Kasaragod town. According to popular tradition, Islam was brought to Lakshadweep islands, situated just to the west of Malabar Coast, by Ubaidullah in 661 CE. His grave is believed to be located on the island of Andrott. A few Umayyad (661–750 AD) coins were discovered from Kothamangalam in the eastern part of Ernakulam district.