3T3 may refer to:

• Boyceville Municipal Airport, an airport located in Wisconsin
• 3T3 cells, a cell line established in 1962 by two scientists at the Department of Pathology in the New York University School of Medicine

• Trier railway station
• Trier Social Stress Test
• Trier Valley
• Trier valley
• Trierweiler (disambiguation)
• Trier-West/Pallien
• Trier West Railway
• Trier-Zewen
• Triesdorf Bahnhof
• Triesh
• Triesman
• Trieste airport
• Trieste (album)
• Trieste bathyscaphe
• Trieste Bay
• Trieste chronology
• Trieste Commodity Exchange
• Trieste Commodity Exchange (A Commodity Exchange)
• Trieste Commodity Exchange (Company)
• Trieste del mio cuore
• Trieste Film Festival
• Trieste Karst
• Trieste Mechanized Brigade
• Trieste National Hall
• Trieste Opera