Adopting a theoretical framework throughout the clinical practice guideline (CPG) process (development, dissemination, implementation, and evaluation) can be useful in systematically identifying, addressing, and explaining behavioral influences impacting CPG uptake and effectiveness. This article argues that using a theoretical framework should increase the utility and probably the implementation of a CPG. A hypothetical scenario is provided using the theory of planned behavior (TPB) to aid in our explanation. While other theories may be viable, the TPB is chosen because it accounts for a wide spectrum of behavioral factors known to influence physician behavior, and because its flexibility allows it to be used for different populations (e.g., specialists), behaviors, and contexts (e.g., hospital, private clinic). In addition, evidence has indicated that the TPB can influence physician behavior. Empirical research examining whether CPG utility can be significantly improved by appropriately selecting and implementing theory throughout the CPG process is warranted.