William Jack

• William Jack (athlete), British Olympic sprinter
• William Jack (Australian explorer), founder of Herberton, Queensland
• William Jack (Australian politician)
• William Jack (botanist), of Scotland
• William Jack (mathematician), from Scotland
• William Jack (U.S. politician), member of the U.S. House of Representatives
• William Brydone Jack, Canadian mathematician and astronomer
• William Houston Jack, Republic of Texas congressman and soldier