The present work reviews the literature examining connections involving the key constructs of optimism and pessimism with motivation and adjustment. We review historical and conceptual models of optimism and pessimism. We then examine how these central constructs have been linked to both adaptive and maladaptive motivational processes and outcomes in the empirical literature. How cultural factors may impact the function of optimism and pessimism is also discussed. We end with a brief discussion of emerging issues that would be useful to examine in future research on optimism and pessimism.