This thesis goal was to test the role of mood in the mobilisation of mental effort. Based on the Mood-Behavior-Model, study 1 intended to clarify that mood effects on effort mobilization are context-dependent; study 2 was designed to provide a more conclusive test of mood informational impact on behavior-related judgments; and studies 3 and 4 manipulated judgment context itself, while accounting for the context-dependency of moods. Effort mobilization was operationalized as cardiovascular reactivity. Results support that: 1) moods by themselves are not stable motivational states; 2) effort mobilization only occurs in contexts that explicitly demand effort; 3) mood will only be used as information for demand appraisals and effort mobilization if people remain unaware of their affective state; 4) mood's effect on effort mobilization is context-dependent. Thus, moods per se do not involve effort-related autonomic adjustments, but they can impact effort-related autonomic reactivity during task performance and self-regulation.