Stephen Gary "Steve" Wozniak (born August 11, 1950), known as "Woz", is an American inventor, computer engineer and programmer who co-founded Apple Computer (now Apple Inc.) with Steve Jobs and Ronald Wayne. Wozniak single-handedly invented both the Apple I and Apple II computers in the late 1970s. These computers contributed significantly to the microcomputer revolution.

The name on Wozniak's birth certificate is "Stephan Gary Wozniak", but Steve's mother said that she intended it to be spelled "Stephen", and "Stephen" is what he uses.Wozniak has been referred to frequently by the nickname "Woz" or "The Woz".; "WoZ" (short for "Wheels of Zeus") is also the name of a company Wozniak founded. During the early 1970s, he was also known as "Berkeley Blue" in the phone phreak community.

Wozniak was born in San Jose, California, the son of Margaret Elaine (Kern) and Jacob Francis "Jerry" Wozniak. He is of Polish and German ancestry on his father's side, and of German, Northern Irish, and English descent on his mother's. Wozniak's friend at the time, Steve Jobs, was assigned to create a circuit board for the arcade video game Breakout. According to Atari co-founder Nolan Bushnell, Atari offered $100 for each chip that was eliminated in the machine. Jobs had little specialized knowledge of circuit board design and made a deal with Wozniak to split the fee evenly between them if Wozniak could minimize the number of chips. Wozniak reduced the number of chips by 50 by using RAM for the brick representation. Too expensive to use at the time, the fact that this prototype also had no scoring or coin mechanisms meant Woz's prototype could not be used. Jobs was paid regardless.