The following highways are numbered 342:

Australia

- Lockington Road

Canada

• Manitoba Provincial Road 342
• Newfoundland and Labrador Route 342
• Prince Edward Island Route 342
• Quebec Route 342
• Saskatchewan Highway 342

Japan

• Japan National Route 342

United States

• Arkansas Highway 342
• Florida:
  • County Road 342 (Gilchrist County, Florida)
  • County Road 342 (Leon County, Florida)
• Georgia State Route 342 (former)
• Indiana State Road 342
• Louisiana Highway 342
• Maryland Route 342
• Nevada State Route 342
• New York:
  • New York State Route 342
    • New York State Route 342 (former)
• Ohio State Route 342
• Puerto Rico Highway 342
• Tennessee State Route 342
• Texas:
  • Texas State Highway 342
  • Texas State Highway Spur 342
• Virginia State Route 342
• Wyoming Highway 342