OPR may refer to: Office of Planning and Research, an agency of the California government Office of Population Research, the oldest population research center in the United States Office of Professional Responsibility, part of the United States Department of Justice Office of Professional Responsibility (IRS), part of the United States Internal Revenue Service responsible for investigating suspected practitioner misconduct Office of Public Roads, a predecessor of the United States Federal Highway Administration Official Pattern Release, used by Trend Micro to refer to the definitions for their antivirus products Oregon Pacific Railroad (1880–94), in Oregon, United States Oregon Pacific Railroad (1997), in Oregon, United States Old Parochial Registers of the Church of Scotland Output Recordings, a British independent record label run by Trevor Jackson, between 1996–2006 Outward Processing Relief, a 1989 U.K. statutory instrument Overall pressure ratio, the ratio of the stagnation pressure as measured at the front and rear of the compressor of a gas turbine engine Overland Park Regional Medical Center, a hospital in Overland Park, Kansas Overnight Policy Rate, an overnight interest rate set by Bank Negara Malaysia used for monetary policy direction Owner's project requirements, a foundational document for the design and commissioning of buildings; see New-construction building commissioning Rodrigues People's Organisation (Organisation du Peuple Rodriguais), a Mauritian political party See also Operator (disambiguation)