Who is the founder of Hinduism?” This is one of the most basic questions asked about Hinduism. It is so obvious because all the other religions in this world have founders. E.g. Christianity was founded by Jesus Christ, Islam was founded by Hajrat Mohammad Paigambar, Buddhism by Gautam Buddha and so on. So as Hinduism is a religion, there must be some founder. The answer for this question is that actually there is no single founder of Hinduism as Hinduism was not founded as a religion. It was a culture basically flourished in India, which later took the form of a great religion. It would be easy to understand who is the founder of Hinduism if you know what Hinduism actually is.
The modern form of Hinduism is actually a mixture of teachings from Vedas mainly plus teachings of ancient Rishis and some great saints and regional customs and traditions. Hinduism changes with time without disturbing its basic teachings and different deities, which Hindus worship. But Vedas are the main base of Hinduism.
Vedas are believed to be imparted from God to human beings some thousands years ago and were carried forward through teacher-disciple tradition (Gury-Shishya Parampara). So, as Vedas were created by God, we can say that God, Himself, is the founder of Hinduism, which he updates from time to time by reincarnating Himself on the Earth.