The following highways are numbered 324:

Brazil

• BR-324

Canada

• Nova Scotia Route 324
• Saskatchewan Highway 324

China

• China National Highway 324

Costa Rica

• National Route 324

Japan

• Japan National Route 324

United States

• Arkansas Highway 324
• Georgia State Route 324
• Louisiana Highway 324
• Maryland Route 324 (unsigned)
• Minnesota State Highway 324 (former)
• New Jersey Route 324
• New York:
  • New York State Route 324
  • County Route 324 (Erie County, New York)
• Ohio State Route 324
• Pennsylvania Route 324
• Puerto Rico Highway 324
• South Carolina Highway 324
• South Dakota Highway 324
• Texas State Highway 324 (former)
• Virginia State Route 324
  • Virginia State Route 324 (former)
• Montana Highway 324