William Henry Gates III was born in Seattle, Washington, to William H. Gates Sr., a lawyer, and Mary Maxwell Gates, a businesswoman and schoolteacher. His upbringing in an upper-middle-class family provided him with a nurturing environment and access to quality education, fostering his early intellectual curiosity and drive.

Gates demonstrated a keen interest in technology from a young age. While attending the Lakeside School, a private preparatory school, he was introduced to computers and quickly developed a fascination with programming. He, along with his friend Paul Allen, spent countless hours learning and experimenting with the school's computer systems.