P.S. commonly refers to:

• Postscript, writing added after the main body of a letter

PS, P.S., or ps may also refer to:

• PS Publishing, based in the UK
• PS Magazine, a U.S. Army magazine
• Popular Science, a U.S. magazine
• PlayStation Magazine (disambiguation)

• PS Classics, a record label
• P.S. (album), a compilation album of film music by Goran Bregovic
• P.S. (A Toad Retrospective), a compilation album of music by Toad The Wet Sprocket
• "PS", 2003 song by The Books from the album The Lemon of Pink
• "P.S.", 1993 song by James from the album Laid

• P.S. (film), a 2004 film
• P.S., a 2010 film by Yalkin Tuychiev
• PS (TV series), a German television series
• Prompt corner or prompt side, an area of a stage
• P.S. (Doctor Who), a mini episode of the seventh series of Doctor Who

• PlayStation, a video gaming brand owned by Sony
• PlayStation (console), a home video game console by Sony
• Ponniyin Selvan (disambiguation), Indian media franchise, abbreviated PS

• iPhrothiya yeSiliva, a South African military award
• Padma Shri, an Indian civilian award

• Pashto language (ISO 639:ps)
• Proto-Semitic language, a hypothesized proto-language
• The sound of Greek letter psi (ψ)

• Palau (FIPS PUB 10-4 territory code PS)
• State of Palestine (ISO 3166 country code PS)
• MoMA PS1, an art institution in New York

• PS – Political Science & Politics, academic journal
• Parti Socialiste (disambiguation), French
• Partido Socialista (disambiguation), Spanish and Portuguese
• Partito Socialista (disambiguation), Italian
• Polizia di Stato, Italian national police force
• Positive Slovenia
• Pradeshiya Sabha, a unit of local government in Sri Lanka
• Progressive Slovakia Progresívne Slovensko
• Social Democratic Party (Andorra) Partit Socialdemòcrata
• Socialist Party (Netherlands)
• Socialist Party of Albania Partia Socialiste
• Socialist Party of Chile Partido Socialista de Chile
• Socialist Party of Romania Partidul Socialist [din România]
• Finns Party Perussuomalaiset
• Movement of Socialists (Pokret socijalista), a political party in Serbia

• Pastors, ministers in some Christian churches
• Psalms, a book in the Tanakh and Christian Bibles

• Petasecond (Ps), 10¹⁵ seconds
• Picosecond (ps), 10⁻¹² seconds
• Pferdestärke (PS), abbreviation of the German term for metric horsepower
• Picosiemens (pS), SI unit of electric conductance

• Adobe Photoshop, a graphics editor and creator by Adobe
• MPEG program stream, an MPEG-2 container format
• Parametric Stereo, feature used in digital audio
• PostScript, a page description language
  • .ps, filename extension for a file in PostScript format
• ps (Unix), an application that displays statistics on running processes
• .ps, Palestinian Internet domain extension or top-level domain (ccTLD)
• PS Power and Sample Size, an interactive computer program for power and sample size calculations
• Windows PowerShell, a command line scripting and system management shell for Microsoft Windows

• Panayiotopoulos syndrome, a childhood seizure disorder
• Progeroid syndromes, a group of rare diseases causing premature aging
• Pulmonary stenosis or pulmonic stenosis, obstruction of the pulmonary artery of the heart

• P_s or static pressure, in fluid mechanics and aviation
• Proton Synchrotron, a 1959 particle accelerator at CERN
• Chloropicrin, a highly toxic chemical compound
• Persulfate, a class of peroxide sulfate used as a powerful oxidizing agent
• Phosphatidylserine, a phospholipid
• Phosphorothioate (or thiophosphate), a family of compounds and anions with the general chemical formula PS_4−xO_x³⁻ (x = 0, 1, 2, or 3)
• Polystyrene, a common type of plastic
• Ps, positronium, pseudo-chemical symbol

• Paddle steamer, abbreviated PS in vessel prefixes
• Power Stage, a World Rally Championship special stage
• Power steering, a device that helps with steering vehicles
• Pacific Southwest Airlines (1949-1988), IATA designator of former airline
• Ukraine International Airlines, IATA airline designator since 1992
• South Papua (vehicle registration prefix PS)

• Planning Service, Department of the Environment (Northern Ireland)
• Plastic Surgery, abbreviated as P.S. for simple use
• Police sergeant
• Power supply
• Professional services, abbreviated P.S. in name suffixes
• State school or public school, in the US and other countries

• P.S. I Love You (disambiguation)
• PSS (disambiguation)