OPD may refer to: Police departments Oakland Police Department, a U.S. law enforcement agency in California Omaha Police Department, a U.S. law enforcement agency in Nebraska Orlando Police Department, a U.S. law enforcement agency in Florida Other uses o-phenylenediamine, a chemical compound Object Process Diagram, in object oriented programming One Per Desk, a 1980s personal computer and telecommunications terminal Optical path difference Organizational Process Definition Outpatient department, part of a hospital Overfill Protection Device, a safety mechanism incorporated in the valves of propane cylinders Pico dos Dias Observatory, a Brazilian astronomical observatory Office of Public Diplomacy, a US propaganda agency during the Reagan era Organic personality disorder See also OPDS (disambiguation)