PMS is a three-letter initialism which may mean:

Professor of Military Science, the commander of an Army ROTC unit

Philips Medical Systems, a division of the electronics company Philips

Package management system, a collection of programs that assist with manipulating software packages on Unix-like computers

Premenstrual syndrome, a collection of physical, psychological and emotional symptoms related to a woman's menstrual cycle

POS management system (Point of sale management system)

Project Management Software

PMS (gene), a gene whose mutation may cause Hereditary nonpolyposis colorectal cancer

P.M.S. Hacker, a British philosopher

Perth Modern School, an elite, academically selective government secondary school located in Perth, Western Australia.

Practice Management Software

Peninsula Medical School, Devon and Cornwall, UK

Pantone Matching System, a colour space

Presidential Management Staff (Philippines)

Potassium metabisulfite, an antioxidant and chemical sterilant

Plaza Middle School, in Virginia Beach, Virginia, USA

Providence Middle School, in Chesterfield County, Virginia, USA

Pleasanton Middle School, in Pleasanton, California, USA

Pretty Mean Sisters, a stable in the World Wrestling Federation

Property management system, systems that run hotels (such as MICROS Fidelio/Opera, or InnQuest Software's roomMaster 2000)

Pre-main sequence star, in astronomy, is a star that has not yet reached the main sequence

Pop'n Music Script, a computer file format

Postmarketing surveillance

Prime Minister's Spokesman

Pioneer Middle School, in Cooper City, Florida, USA

PMS Clan, Pandora's Mighty Soldiers, an all-female gaming clan

power management system (such as Cool'n'Quiet and SpeedStep)

The Piedmontese language has the language code: pms.

PMS, a Mary J. Blige song included in her 2001 album No More Drama

Pillsbury, Madison & Sutro, a law firm now known as Pillsbury Winthrop Shaw Pittman.

Piedmont Middle School, in Piedmont, California