Williamstown is the name of several places in the Australia:

• Williamtown, New South Wales
• Williamstown, South Australia
• Williamstown, Victoria, which gives it's name to the Williamstown railway line, Melbourne, and Williamstown railway station, Melbourne

Williamstown is the name of several places in the United States of America:

• Williamstown, Kentucky
• Williamstown, Massachusetts
• Williamstown, New Jersey
• Williamstown, New York
• Williamstown, Pennsylvania
• Williamstown, Vermont
• Williamstown, West Virginia
• Williamstown, Wisconsin
• Williamstown Township, Michigan

There are also places named Williamston; see also Williams, Williamsburg, Williamson, Williamsport, and Williamsville.