- Osage Tribe, Oklahoma1
- Pepper, Claude, 1900-19891
- Poage, W. R. (William Robert), 1899-19871
- Ponca Tribe of Indians of Oklahoma1
- Preyer, Richardson1
- Pritchard, Joel M. (Joel McFee), 1925-19971
- Public Citizen, inc. Congress Watch1
- Rangel, Charles B.1
- Reagan, Nancy, 1921-20161
- Rinaldo, Matthew J.1
- Rockefeller, Nelson A. (Nelson Aldrich), 1908-19791
- Rodino, Peter W., Jr., 1909-20051
- Roncalio, Teno, 1916-20031
- Rostenkowski, Dan1
- Roy, William R.1
- Santini, Jim, 1937-20151
- Sawhill, John C., 1936-1
- Schroeder, Pat1
- Scott, Hugh, 1900-19941
- Seminole Nation of Oklahoma1
