Various theories related to stress, coping, and trauma have application to PTG in various ways. In this chapter we review such theories, including conservation of resources theory, terror management theory, mortality salience and reminders, empowerment, and mindfulness. We also look at models that overlap with PTG but that are distinct from it in a number of ways. These models include stress-related growth, benefit finding, thriving, and flourishing. We also discuss research and perspectives about the relationship between PTG and PTSD, and the difference between PTG and resilience. The chapter concludes with research that has examined behavioral and personality changes shown to relate to and/or provide evidence of PTG.