A questionnaire was given to samples of the public (N = 1149) and of professionals within the criminal justice system (N = 292) in the State of Washington. Contrary to expectation, the data indicated that the public had the most knowledge about the correctional system followed by the courts and police. The same was true for the sample of criminal justice professionals. The public was significantly less knowledgeable than the professionals concerning the courts and corrections, but not on items concerning the police. With few exceptions, the data displayed little association between socio-demographic and experience variables and knowledge about the criminal justice system. In terms of support, the public rated the police much higher than either the courts or corrections. Finally, a relatively weak relationship existed between knowledge and support, with increased knowledge generally reducing support. (Author abstract)