Are we flexible in using different strategies to regulate our emotions during our daily functioning? What are the personal and situational mechanisms accounting for this complex set of emotion regulation (ER) processes? And to what extent different forms of ER flexibility are adaptive? Current empirical evidence challenges a static view of ER strategies as inherently adaptive or maladaptive. This has led contemporary accounts to consider the variation in use of ER strategies across time depending on the complex interplay of personal characteristics, specific situational demands, and motivational goals. However, despite the relevance of these new approaches and their obvious theoretical and practical implications, the study of ER flexibility is a relatively young research field, still lacking common integrative views. In this paper, I briefly discuss the shared and unique components across different theoretical frameworks of ER flexibility and make recommendations for future research to advance the understanding of this crucial phenomenon. I identify specific questions that may be contrasted through programmatic research lines and propose that the integration of cognitive mechanisms known to affect ER may help to advance the science of ER flexibility. I also enumerate a series of methodological approaches that can be used to tests proposed models of ER flexibility. Finally, I highlight potential practical implications that can be derived from these new research programs in order to improve interventions aimed at promoting adaptive ER flexibility and adaptive functioning.