First published in 1975, the McGill Pain Questionnaire (MPQ) is an often-cited pain measure, but there have been no systematic reviews of the MPQ in cancer populations. Our objective was to evaluate the MPQ as a multidimensional measure of pain in people with cancer. A systematic search of research that used the MPQ in adults with cancer and published in English from 1975 to 2009 was conducted. Twenty-one articles retrieved through computerized searches and nine studies from manual searches met the criteria. Review of the 30 studies demonstrated that pain intensity (n = 29 studies) and pain quality (n = 27 studies) were measured more frequently than pain location, pattern, and behavior parameters. Measuring cancer pain using the MPQ provided insights about disease sites, magnitude of pain, and effectiveness of treatment and intervention. Additionally, the MPQ data informed speculations about pain mechanisms, emotional status, overall sensory pain experience, changes in pain over time, and alleviating and aggravating behaviors/factors. Findings supported the MPQ as an effective multidimensional measure with good stability, content, construct, and criterion validity and showed sensitivity to treatment or known-group effects. The MPQ is a valid, reliable, and sensitive multidimensional measure of cancer pain. Cancer pain is a subjective complex experience consisting of multiple dimensions, and measuring cancer pain with the MPQ may help clinicians to more fully understand whether those dimensions of cancer pain influence each other. As a result, clinicians can provide better and effective cancer pain management.