Who is the deity of Buddhism?

Buddhists do not worship any Gods but the founder of Buddhism is the Buddha (Siddhartha Gautama) and He is greatly respected.
There is no diety in Buddhism. The Buddha was never a god. He did not consider himself one, and when asked, he denied any claim to divinity. Buddhism does not call for the worship of any diety, although one can still worship God... Buddhism is not a religion but a practice... a philosophy. There are Christian Buddhists, Jewish Budddhists, et cetera. I myself am a Buddhist and I believe in God and I believe in Jesus. :-) Buddhism is very accepting.