PDI may refer to:

Organizations

• Investigations Police of Chile ()

• Party for Justice and Integration (), an Albanian political party

• Pacific Data Images (1980-2015), an American computer animation company

• Paul Drude Institute for solid state electronics, German research institute

• Philippine Daily Inquirer, a newspaper

• Plumbing & Drainage Institute, US

• Ideal Democratic Party, political party in Rwanda

• Partai Demokrasi Indonesia (Indonesian Democratic Party) (1973–2004), a defunct political party

• Polo Democrático Independiente (Independent Democratic Pole), a Colombian democratic political party

Chemistry and biochemistry

• Pyridinediimine, organic compounds used as ligands

• Perylenediimide, a rylene dye

• Photodynamic inactivation, or antimicrobial photodynamic therapy

• Protein dispersibility index, in water

• Protein disulfide isomerase, an enzyme

• Polydispersity index, molecular weight distribution of polymers

• Pentamethylene diisocyanate, a bio-based diisocyanate prepared from pentamethylene diamine

Computing

• Pentaho Data Integration, design data flow software

• Versit Consortium's Personal Data Interchange

• Pop Directional Isolate, Unicode bidirectional text character

• Portable Database Image format (.pdi)

• Atmel Program and Debug Interface

Other

• Pacific Deterrence Initiative, a deterrence framework by the United States Department of Defense

• Postal Development Indicator, a UPU ranking

• Peripheral drift illusion, a motion illusion

• Pilot direction indicator, for aircraft bombing

• Power Distance Index, a measure of social power acceptance

• Powered Descent Initiation, of Apollo moon landing