Self-administration of cocaine is known to have both positive/euphoric and negative/anxiogenic effects. Although extensive research has been done on the rewarding effects of cocaine, the anxiogenic effects and the neurobiology that give rise to them remain relatively unstudied. Recent research has identified the lateral habenula (LHb) as contributing to the experience of anxiogenic states in laboratory animals. The LHb receives projections from dopaminergic, serotonergic, and noradrenergic brain pathways, all three of which are sites of cocaine action. The intent of this dissertation is to specifically investigate the role of habenular dopamine (DA) in the production of cocaine's anxiogenic effects. Five studies were therefore designed and executed to address three broad aims: (1) to determine if the reward-related neurotransmitter, DA, plays a role in cocaine's negative effects; (2) to assess the role of the lateral habenula in anxious states; and (3) to examine the role of habenular DA receptors in the dual positive and negative effects of cocaine. Altogether, the experiments detailed in this thesis support a role for habenular DA in the behavioral expression of cocaine's anxiogenic effects, and these results are reviewed in the context of the current literature.