P4 may refer to:
Computing Intel Pentium 4, a processor series shipped from 2000 to 2008 The P4 power connector, introduced in the ATX12V 1.0 standard to power these and later CPUs The i486DX (P4) model of the Intel 80486 microprocessor, introduced in 1989 P4 (programming language), for controlling network data forwarding P4, the Perforce software command line client
Media P4 Radio Hele Norge (PFI), a Norwegian radio company Kanal 24 (Kanal 4), which acquired the Norwegian P4 channel from PFI Sveriges Radio P4, a Swedish radio channel Persona 4, a 2008 video game Periphery IV: Hail Stan, a 2019 album by American progressive metal band Periphery PartyNextDoor 4, a 2024 album by Canadian singer PartyNextDoor Psychonaut 4, a Georgian black metal band
Military Skaraborg Regiment (armoured), a Swedish army unit, designated P 4 Peugeot P4, a French military vehicle
Science P4 laboratory, a biosafety level 4 facility Tetraphosphorus (P4), an allotrope of phosphorus Group p4, the plane symmetry group wallpaper group p4 Progesterone (Pregn-4-ene-3,20-dione), a steroid hormone Kerberos, the fourth moon of Pluto Perfect fourth, a musical interval Enterobacteria phage P4 P4, an EEG electrode site according to the 10-20 system P4 cell, a stage in the Caenorhabditis elegans embryonic development P4-metric, in statistics, a performance metric P4, three-dimensional space group number 75 P, three-dimensional space group number 81
Roads P4 road (Latvia) P04 road (Ukraine)
Other uses Papyrus 4, a New Testament manuscript Trans-Pacific Strategic Economic Partnership, or P4, a free trade agreement between Brunei, Chile, New Zealand, and Singapore Prussian P 4, a German steam locomotive Protofour, or P4, a set of standards for model railways
See also 4P (disambiguation) Phosphate, molecular formula Play (telecommunications) P4, a Polish cellular telecommunications provider