PDO can refer to:
- 1,3-Propanediol, an industrial chemical
- The Pacific Decadal Oscillation, a pattern of climate variation
- Paid Day Off, an eight hour long Paid Time Off
- Palladium(II) oxide PdO
- Petroleum Development Oman, an Omani oil company, and the part of the Omani capital region where the company is located
- Philips and Dupont Optical
- Policyholder Dividend Obligation
- Protected Designation of Origin, one of three Protected Geographical Status classifications used in the European Union for protected regional foods
- Pseudo-differential operator, a concept in mathematical analysis
In computing:
- Panzer Dragoon Orta, a 3D shooter created by Smilebit on the Xbox
- Persistent Data Object
- Persistent Domain Object
- PHP Data Objects, a PHP extension that can be used as a database abstraction layer
- Physical Device Object, a type of WDM (Microsoft Windows Driver Model) Device Object; it represents a device on a bus to a bus driver
- Portable Distributed Objects, a version of Cocoa's Distributed Objects for remote use
- Process Data Object, a type of protocol frame in some fieldbuses, for instance, CANopen.
- Python Data Objects, a Python third party library for low level SQL operations