Research on cognitive load theory (CLT) has focused primarily on identifying the mechanisms and strategies that enhance cognitive learning outcomes. However, CLT researchers have given less attention to the ways in which cognitive load may interact with the motivational and emotional aspects of learning. Motivational beliefs have typically been assumed to be merely a precursor to the cognitive process. This view provides an incomplete picture of the dynamic relationship between cognitive load and motivational beliefs. In this review, we synthesize previous scholarly efforts concerning the motivational effects of anticipated investment of mental effort, new developments in the expectancy-value theory of motivation, and recent findings implicating cognitive load in the formulation of motivational beliefs. By conceptualizing cognitive load as motivational cost, we argue that motivational beliefs are an important outcome that results from instruction. We examine recent empirical evidence supporting this proposition and consider the implications for the further development of both CLT and motivational theories through their integration.