TF3 may refer to:

• Theaflavin digallate
• The promotional abbreviation for Dark of the Moon, the third live-action Transformers film
• Time for Three string trio
• SS Train Ferry No. 3

• Magnadoodle
• Magnadyne Livorno
• Magnae Carvetiorum
• Magnaflux
• Magna Germania
• Magnago
• Magna graecia
• Magna Graecia University of Catanzaro
• Magna Græcia University
• Magnaguards
• Magna Hungaria
• Magnalium
• Magnanapoli
• Magnaneries
• Magnanery
• Magnanime class ship of the line
• Magnanimity
• Magnanimous
• Magnanimous Records
• Magnano
• Magnano in Riviera
• Magnant
• Magna Pacific
• Magnapinna atlantica
• Magnapinna pacifica