Tonk was a princely state of India which by treaty in 1817 accepted British suzerainty. Following the Partition of India in 1947, Tonk acceded to the newly independent Union of India. It was located in the region that is now the Tonk district.

The founder of the state was Amir Khan (1768-1834), a Muslim adventurer and military leader of Afghan descent. In 1817, upon submitting to the British East India Company, he received the territory of Tonk and the title of Nawab. While retaining internal autonomy and remaining outside British India, the state came under the supervision of the Rajputana Agency and consisted of six isolated tracts, some of which were under the Central India Agency.

In 1947, on the Partition of India whereby India and Pakistan gained independence, the Nawab of Tonk decided to accede to the Union of India. Subsequently, most of the area of the state of Tonk was integrated into the Rajasthan state, while some of its eastern enclaves became part of Madhya Pradesh.

The foundation of the principality of Tonk led to the creation of a large Rajasthani Pathan community.