Stephen Gary Wozniak (/ˈwɒzniæk/; born August 11, 1950), also known by his nickname “Woz”, is an American technology entrepreneur, electronics engineer, computer scientist, computer programmer, philanthropist, and inventor. In 1976, he co-founded Apple Computer with his late business partner Steve Jobs, which later became the world’s largest technology company by revenue and the largest company in the world by market capitalization. Through his work at Apple in the 1970s and 1980s, he is widely recognized as one of the most prominent pioneers of the personal computer revolution.

In 1975, Wozniak started developing the Apple I  into the computer that launched Apple when he and Jobs first began marketing it the following year. He primarily designed the Apple II, introduced in 1977, known as one of the first highly successful mass-produced microcomputers, while Jobs oversaw the development of its foam-molded plastic case and early Apple employee Rod Holt developed its switching power supply. With human–computer interface expert Jef Raskin, Wozniak had a major influence over the initial development of the original Apple Macintosh concepts from 1979 to 1981, when Jobs took over the project following Wozniak’s brief departure from the company due to a traumatic airplane accident. After permanently leaving Apple in 1985, Wozniak founded CL 9 and created the first programmable universal remote, released in 1987. He then pursued several other businesses and philanthropic ventures throughout his career, focusing largely on technology in K–12 schools.

As of February 2020, Wozniak has remained an employee of Apple in a ceremonial capacity since stepping down in 1985.

In recent years, he has helped fund multiple entrepreneurial efforts dealing in areas such as GPS and telecommunications, flash memory, technology and pop culture conventions, technical education, ecology, satellites and more.