The Dooars or Duars (Bengali: ডুয়ার্স; Nepali: डुवर्स) are the floodplains and foothills of the eastern Himalayas in North-East India around Bhutan. Duar means door in Assamese, Nepali, Maithili, Bhojpuri, Magahi and Bengali languages, and the region forms the gateway to Bhutan from India.

There were 18 passages or gateways through which the Bhutanese people can communicate with the people living in the plains. This region is divided by the Sankosh river into the Eastern and the Western Dooars, consisting of an area of 8,800 km² (3,400 sq mi). The Western Dooars is known as the Bengal Dooars and the Eastern Dooars the Assam Dooars. Dooars is synonymous with the term Terai used in Nepal and northern India.

The history of the Dooars is very old. According to current historical research carried out by Dr. Sailen Debnath, an eminent scholar of the region, the Dooars was the seat of the medieval Kamata kingdom. Kamatapur emerged as a sovereign state from the middle of the seventh century. Most probably, Nalrajar Garh in Chilapata Forest was the earliest capital of Kamatapur, and subsequently through various ups and downs the capital was shifted to Mainaguri and then to Prithu Rajar Garh before its final shifting to Gosanimari, an ancient port-town since the seventh century. After the kingdom of Kamatapur as was devastated by Alauddin Husain Shah of Gaur in 1494, there emerged the Koch kingdom again in the Dooars under the leadership of Vishwa Singha. Hingulavas near Mahakalguri in the Dooars was the earliest capital of the Koch kingdom. It was long after that the Koch capital was shifted to Atharakota and then ultimately to present Cooch Behar town.

Taking advantage of the weakness of the Koch kingdom in subsequent times, Bhutan took possession of the Dooars. This region was controlled by the kingdom of Bhutan when the British annexed it in 1865 after the Bhutan War under the command of Captain Hedayat Ali. The area was divided into two parts: the eastern part was merged with Goalpara district in Assam and the western part was turned into a new district named Western Dooars. Again in the year 1869, the name was changed to Jalpaiguri District. After the end of the British rule in India in 1947, the Dooars acceded into the dominion of India and it merged with the Union of India shortly afterwards in 1949.