The Khalji dynasty (Bengali: খলজি রাজবংশ, Persian: خاندان خلجی) was the first Muslim dynasty to rule the Bengal region in the Indian subcontinent. The dynasty, which hailed from the Garmsir region of present-day Afghanistan, was founded in 1204 by Muhammad Bakhtiyar Khalji, a Muslim Turko-Afghan general of the Ghurid Empire. The Khaljis initially pledged allegiance to Sultan Muhammad of Ghor until his death in 1206, though their rule in Bengal was mostly independent. Under the rule of Iwaz Khalji, Bengal experienced major developments such as its first naval force, flood defence systems and linkage with the Grand Trunk Road. The dynasty was based in the city of Lakhnauti in northern Bengal, later expanding eastwards and southwards. Nasiruddin Mahmud, the son of Mamluk sultan Iltutmish of Delhi managed to conquer Bengal in 1227; although the Khaljis briefly reasserted their independence, they surrendered to the Mamluks in 1231, who replaced them with a series of regional governors.

The Khalji dynasty was of Turko-Afghan origin. Its ancestors, the Khalaj, are said to have been initially a Turkic people or a Turkified people of possibly of Indo-Iranian origin who migrated together with their ancestors the Hunas and Hephthalites from Central Asia, into the southern and eastern regions of modern-day Afghanistan as early as 660 CE, where they ruled the region of Kabul as the Buddhist Turk Shahis. According to R.S. Chaurasia, the Khaljis slowly inherited many Afghan habits and customs, and that they were treated as Afghans by the Turkic nobles of the Delhi Sultanate. Even to the point where Turkic nobles in the Delhi Sultanate opposed Khalji ascension to the throne of Delhi after the Khalji Revolution.

According to The New Cambridge History of Islam in the thirteenth century the Khalji were regarded as a separate people distinct from the Turks. The later so-called “Khalji Revolution” was the transfer of power from a Turkish ruling elite to a non-Turkish one.

André Wink however, states that Khaljis were a Turkicized group and remnants of early Indo-European nomads such as Kushans, Hephthalites, and Sakas who later merged with the Afghans. Also, stating that "at that time they were not perceived as Turks or Mongols. Contemporary historians clearly distinguish the Khaljis from the Turks"

The Khalaj are, according to Doerfer, perhaps of Sogdians who were Turkicized. These Khalaj were later Afghanized and are believed to be the ancestors of Ghilzai/Ghilji Pashtuns.

Many of them traced their origins to Garmsir and under the leadership of Muhammad Bakhtiyar Khalji, they desired to be employed by the provincial Delhi army of the Ghurid Empire. After being refused rank by Delhi governor Qutb al-Din Aibak, the Khaljis proceeded eastwards where they commanded different troops and were granted land-estates in places such as Mirzapur.

In a short amount of time, the Khaljis became established and Bakhtiyar began to successfully carry out raids towards the east. After subjugating Bihar in 1200, his forces entered Nabadwip in Bengal three years later. Subsequently, Bakhtiyar went on to capture the capital and the principal city, Lakhnauti, and conquered much of Bengal.

Given the considerable overland distance between Delhi and Bengal, the Khaljis had carved an independent territory of their own, establishing their own administrative system. Bakhtiyar became the dynasty's first ruler, and the conquered territory was divided into jagirs which were granted to other Khalji tribesmen. Iwaz Khalji was appointed to govern Kangori and Ali Mardan Khalji in Devkot.