Although physical activity interventions have been shown to effectively modify behavior, little research has examined the potential of these interventions for adoption in real-world settings. The purpose of this literature review was to evaluate the external validity of 57 theory-based physical activity interventions using the RE-AIM framework. The physical activity interventions included were more likely to report on issues of internal, rather than external validity and on individual, rather than organizational components of the RE-AIM framework, making the translation of many interventions into practice difficult. Furthermore, most studies included motivated, healthy participants, thus reducing the generalizability of the interventions to real-world settings that provide services to more diverse populations. To determine if a given intervention is feasible and effective in translational research, more information should be reported about the factors that affect external validity.