Clinical practice guidelines (CPGs) have been widely used in healthcare policy, practice, and for suggesting future research. As patients increasingly become involved in CPG development to produce patient-centered recommendations, more research is needed on methods to engage patients, particularly methods allowing for scalable engagement of large, diverse, and geographically distributed groups of patients. In this article, we discuss practical considerations for using online methods to engage patients in CPG development. To inform this discussion, we conducted a rapid, systematic review of literature on patient involvement in CPG development and used qualitative evidence synthesis techniques to make inferences about potential advantages and challenges of using online methods to engage patients in this context. We identified 79 articles containing information about involving patients in CPG development. Potential advantages include the ability of online methods to facilitate greater openness and honesty by patients, as well as to reflect the diversity of patient views, which in turn further improve the utility of CPGs. Potential challenges of using online methods may include the extra skill, time, and certain types of resources that may be needed for patient engagement, as well as the difficulty engaging specific patient populations. However, these challenges are mitigated by growing calls for patient engagement as normative for CPG development in addition to patients' increasing familiarity with online technologies. These practical considerations should be examined empirically as guideline development groups further explore the appropriateness of using online methods to engage patients across different stages of CPG development.