Who is known as the father of Dyarchy?

Sir Lionel Curtis is known as the father of the Dyarchy. Dyarchy was a system of double government introduced by the Government of India Act (1919) for the provinces of British India.

Lionel George Curtis (1872–1955) was a British official and author whose writings influenced the evolution of the Commonwealth of Nations.

For further reading check the following articles:

• Government of India Act, 1919
• Legislations in British India