- William Kloos
- William Knowles
- William Koch
- William Kogan
- William Kolb
- William Komaroff
- William Kontaxis
- William Kremer
- William Kridel, Jr
- William Kucera
- William Laboratories Overview
- William Lafferty
- William Lapthorn
- William Lawrence
- William Lentine
- William Lenz
- William Lewis
- William Lindström
- William Lo
- William Lynch
- William Lyon Homes Overview
- William M. Bird and Company Overview
- William Macaulay
- William Maher
- William Malpica
- William Marraccini
- William Marshall
- William Maslechko
- William Matthews
- William May
- William McBride Jr.
- William Mccartney
- William McDiarmid
- William Mcdonough
- William McGugin
- William McKee
- William Mckinley
- William Mckinley
- William McLean
- William McMullan