Thapa dynasty or Thapa noble family also known as Dynasty of Borlang was a Chhetri political family that handled Nepali administration affairs between 1806 and 1837 A.D. and 1843 to 1845 A.D. as Mukhtiyar. This was one of the four noble families to be involved in the active politics of the Kingdom of Nepal, along with the Shah dynasty, Basnyat family, and the Pande dynasty before the rise of the Rana dynastyor Kunwar family. At the end of 18th century, Thapas had extreme dominance over Nepalese Darbar politics alternatively contesting for central power against the Pande family. Bir Bhadra Thapa was a Thapa of Chhetri group and leading Bharadar during Unification of Nepal. His grandson Bhimsen Thapa became Mukhtiyar of Nepal and established Thapa dynasty to the dominating position of central court politics of Nepal.

Chhetri, historically called Kshettriya or Kshetriya or Khas are Nepali speaking Rajputs of Khas community, some of whom trace their origin to migration from medieval India. Chhetri was a caste of administrators, governor and military elites in the medieval Khas Kingdom and Gorkha Kingdom. The nobility of the Gorkha Kingdom mainly originated from Chhetri families. They also had a strong presence in civil administration affairs. The bulk of prime ministers of Nepal before the democratization of Nepal belonged to this caste as a result of the old Gorkhali aristocracy. Gorkha-based aristocratic Chhetri families included the Pande dynasty, the Basnyat dynasty, the Kunwar family, and the Thapa dynasty,.