401 may refer to:

• 401 (number), the natural number following 400 and preceding 402
• A year: 401 BC or AD 401
• Ontario Highway 401, a highway that extends across Southern Ontario, Canada
  • There are also other roads named 401, see the List of highways numbered 401
• 401(a), a type of U.S. tax-deferred retirement savings plan defined by a subsection of the Internal Revenue Code
• 401(k), a type of U.S. employer-sponsored retirement plan defined by a subsection of the Internal Revenue Code
• Titanic The hull number for RMS Titanic
• Bristol 401, a car produced by Bristol Cars in the early 1950s
• HTTP 401, a status in the HTTP protocol indicating authentication has failed
• .401 Winchester Self-Loading centerfire rifle cartridge introduced in 1910
• Area code 401, NANP area code that serves the entire state of Rhode Island
• Cessna 401, an airplane
• Peugeot 401, a family car
• "401", a storyline in the science fiction comedy webtoon series Live with Yourself!

Topics referred to by the same term

This disambiguation page lists articles associated with the same number.
If an internal link led you here, you may wish to change the link to point directly to the intended article.