The Bengal tiger is a population of the Panthera tigris tigris subspecies. It ranks among the largest of wild cats. It is distributed from India, southern Nepal, Bangladesh, Bhutan to Southwestern China. Its historical range extended to the Indus River valley until the early 19th century, and it is thought to have been present in the Indian subcontinent since the Late Pleistocene about 12,000 to 16,500 years ago. It is threatened by poaching, habitat loss and habitat fragmentation.

As of 2022, the Bengal tiger population was estimated at 3,167–3,682 individuals in India, 316–355 individuals in Nepal, 131 individuals in Bhutan and around 114 individuals in Bangladesh.

Felis tigris was the scientific name used by Carl Linnaeus in 1758 for the tiger. It was subordinated to the genus Panthera by Reginald Innes Pocock in 1929. Bengal is the traditional type locality of the species and the nominate subspecies Panthera tigris tigris.

The validity of several tiger subspecies in continental Asia was questioned in 1999. Morphologically, tigers from different regions vary little, and gene flow between populations in those regions is considered to have been possible during the Pleistocene. Therefore, it was proposed to recognise only two subspecies as valid, namely P. t. tigris in mainland Asia, and P. t. sondaica in the Greater Sunda Islands and possibly in Sundaland. The nominate subspecies P. t. tigris constitutes two clades: the northern clade comprises the Siberian and Caspian tiger populations, and the southern clade all remaining continental tiger populations. The extinct and living tiger populations in continental Asia have been subsumed to P. t. tigris since the revision of felid taxonomy in 2017.

Results of a genetic analysis of 32 tiger samples indicate that the Bengal tiger samples grouped into a different clade than the Siberian tiger samples.

The Bengal tiger is defined by three distinct mitochondrial nucleotide sites and 12 unique microsatellite alleles. The pattern of genetic variation in the Bengal tiger corresponds to the premise that it arrived in India approximately 12,000 years ago. This is consistent with the lack of tiger fossils from the Indian subcontinent prior to the late Pleistocene, and the absence of tigers from Sri Lanka, which was separated from the subcontinent by rising sea levels in the early Holocene.

The Bengal tiger's coat is yellow to light orange, with stripes ranging from dark brown to black; the belly and the interior parts of the limbs are white, and the tail is orange with black rings. The white tiger is a recessive mutant, which is reported in the wild from time to time in Assam, Bengal, Bihar and especially in the former State of Rewa. However, it is not an occurrence of albinism. In fact, only one fully authenticated case of a true albino tiger is known, and there are no confirmed cases of black tigers, except for a possible specimen examined in Chittagong in 1846. Fourteen Bengal tiger skins in the collection of the Natural History Museum, London have 21–29 stripes. Another recessive mutant is the golden tiger that has a pale golden fur with red-brown stripes. The mutants are very rare in nature.

The greatest skull length of a tiger is 351 mm (13.8 in) in males and 293 mm (11.5 in) in females. It has exceptionally stout teeth. Its canines are 7.5 to 10 cm (3.0 to 3.9 in) long and thus the longest among all cats.