DF or df may refer to:

• DeFRaG, a modification for the computer game Quake III Arena
• DragonFable, a 2006 video game by Artix Entertainment
• Dwarf Fortress, a 2006 sandbox-style computer game

• Distrito Federal (Brazil), or the Federal District
• Distrito Federal (Mexico), or the Federal District, now known as Mexico City

• Danish People's Party (Dansk Folkeparti)
• Democratic Front (Bosnia and Herzegovina) (Demokratska fronta)
• Democratic Front (Montenegro) (Demokratski front)

• df (Unix), a Unix command to report disk space usage by a filesystem
• Dairy free, identifying products that contain no milk
• Decapacitation factor, in biochemistry
• Degrees of freedom, various measures in statistics, mathematics and physics
• Density function, a mathematical function with a wide range of applications
• Dielectric loss
• Direction finding, a technique used to locate radio transmitters
• Direction flag, a flag stored in the FLAGS register on all x86-compatible CPUs
• Dissipation factor, a measure of loss-rate of energy of an oscillation mode in a dissipative system
• Dongfeng (missile), a Chinese intercontinental ballistic missile
• Dongfeng series of diesel locomotives
  • China Railways DF
  • China Railways DF4
  • China Railways DF8
• Methylphosphonyl difluoride, a chemical weapons precursor
• Daylight factor (DF), the ratio of the light level inside a structure to the light level outside the structure.

• Defender (association football)
• Delta Force, a component of the U.S. Army Joint Special Operations Command
• Design Factory, a department of Aalto University
• Duty Free, goods which are free from tax or duty
• New Zealand DF class locomotive (1979)
• Quantum Air (formerly AeBal), Spanish airline (IATA code DF)

• Dongfeng (disambiguation)