Background: Although internalizing and externalizing problems are often considered in isolation from one another, they frequently co-occur in individuals leading to unique behavioral profiles. Objective: To examine the overlap and divergence of anxious and aggressive behaviors, as well as the differential presence of anxiety within the forms, functions, and subtypes of aggression. Methods: This is a theoretical literature review conducted by reviewing recent manuscripts detailing numerous correlates of anxiety and aggression and then synthesizing them into a potential conceptual model. Results: Conceptualizing anxiety and aggression as behavioral representatives of the fight-or-flight response, this paper considers their overlap and divergence on various emotional (e.g., emotion regulation) and cognitive (e.g., perceptions of control) mechanisms. Variations in these mechanisms as they relate to the forms (relational/overt), functions (proactive/reactive), and form-function subtypes of aggression are also examined. Conclusions: The clinical utility of considering these cognitive and emotional mechanisms when dealing with aggressive behavior is discussed. Concluding remarks seek to conceptualize anxiety and aggression as parts of an interconnected fight-or-flight system.