| Acronym | Definition |
|---|
| PiS | Law and Justice (Poland) |
| PiS | Programa de Integração Social (Social Integration Program, Brazil) |
| PiS | Pigs in Space (band) |
| PiS | Postal Inspection Service (US) |
| PiS | Passenger Information System |
| PiS | Patient Information Sheet (drug trials) |
| PiS | Portfolio Investment Scheme (finance; various companies) |
| PiS | Product Information Sheet |
| PiS | Protocol Interfaces |
| PiS | Project Implementation Schedule |
| PiS | Processing Information Structure |
| PiS | Physical Interfaces |
| PiS | Pharmacy Information System |
| PiS | Production Information System (data processing network) |
| PiS | Pre-Installation Survey |
| PiS | Personnel Identification System |
| PiS | Public Information Specialist |
| PiS | Polarized Ion Source (accelerator technology) |
| PiS | Private Independent School |
| PiS | Polish Intelligence Service |
| PiS | Process Improvement Specialist |
| PiS | Privacy-Invasive Software |
| PiS | Plot Induced Stupidity |
| PiS | Prawo i SprawiedliwoϾ (Law and Justice; Polish political party) |
| PiS | Pompano Indoor Skatepark (Florida) |
| PiS | Politiets IndsatsStyrke (Danish TV show) |
| PiS | Post Implementation Support |
| PiS | Pisidic (linguistics) |
| PiS | PLC Information System |
| PiS | Pressure Indicating Switch |
| PiS | Pacific Insular States |
| PiS | Public Information Services Ltd (UK) |
| PiS | Power Interface Systems (BSMC Power Nigeria Ltd.) |