The event was founded in 2010 at the Saint Petersburg Tiger Summit at a point when wild tigers were facing extinction.
Organisations from across the globe now champion Tiger Day, with supporters including WWF, Traffic, National Geographic and the Smithsonian Institute.
To mark International Tiger Day 2014, here are some facts and figures about the iconic big cat.
There are six main species of tigers living in the wild today: Siberian tigers; Bengal tigers; Indochinese tigers; Malayan tigers; Sumatran tigers and South China tigers. Several subspecies of tigers have already gone extinct, including Bali and Javan tigers.
Tigers can also be categorised by their fur colour. White tigers – possibly the most well-known subtype – are produced when tigers carry a rare gene and were first bred in the early 19th century. It is so rare it only occurs once every 10,000 births.