In everyday life, mental fatigue can be detrimental across many domains including driving, learning, and working. Given the importance of understanding and accounting for the deleterious effects of mental fatigue on behavior, a growing body of literature has studied the role of executive control processes in mental fatigue. In a laboratory setup, participants complete a task that places demands on executive control processes and are later given a transfer task. Generally speaking, decrements to subsequent task performance are taken as evidence that the initial executive control task created mental fatigue through the continued engagement of executive control. Several hypotheses have been developed to account for negative transfer resulting from executive control depletion including cognitive resource depletion and task-switching. In the current study, we provide a brief literature review, specify current theoretical approaches to depletion, and provide a strong empirical test of theories for negative transfer from executive control depletion (i.e., does continued performance of an executive control task negatively transfer to that exact same task).