355th may refer to:

• 355th Fighter Squadron, an inactive United States Air Force unit
• 355th Fighter Wing, a United States Air Force unit assigned to the Air Combat Command's Twelfth Air Force
• 355th Tactical Airlift Squadron, a U.S. Air Force squadron based at Rickenbacker Air National Guard Base
• 355th Troop Carrier Squadron, an inactive United States Air Force unit
• 355th Operations Group, a United States Air Force unit, assigned to the 355th Wing
• 355th Aviation Company, of the United States Army
• No. 355 Squadron RAF, WWII long range bombing squadron of the British Royal Air Force
• 355th Reconnaissance Aviation Squadron, a Cold War era unit of the Yugoslav Air Force

• 355th Infantry Regiment (United States), an infantry regiment of the United States Army
• 355th Division (Imperial Japanese Army), a WWII home defence infantry division
  • 355th Infantry Regiment (Imperial Japanese Army), part of the 355th Division (Imperial Japanese Army)
• 355th Rifle Division, a Soviet WWII infantry division

• 355 (number)
• 355, the year 355 (CCCLV) of the Julian calendar
• 355 BC
• All pages with titles beginning with 355th
• All pages with titles containing 355th
• 355 (disambiguation)