Theories of the criminal justice process continue to develop and mature, as do theories of crime; however, less need has been perceived for theory in evidence-based policy evaluations. The authors argue that more emphasis should be placed in criminal justice and criminology on theoretically robust evaluation research, as doing so can help bridge the divide between two divided disciplines. Examples are provided to illustrate how the gap between criminological and criminal justice theory can be bridged with theory-based evaluation. The authors also highlight resources available to researchers who take us up on our call. Abstract published by arrangement with Sage Journals.