The 5-HT7R is the most recent addition to the burgeoning family of serotonin receptors. Preliminary evidences suggest that it may be involved in depression, control of circadian rhythms, and relaxation in a variety of vascular smooth muscles, indicating the high potential of 5-HT7R ligands as new therapeutic drugs. During the last four years several selective 5-HT7R antagonists have been discovered, and we have recently contributed to this field with the definition of a pharmacophoric hypothesis for 5-HT7R antagonism and a computational model of ligand-receptor interaction of new naphtholactam and naphthosultam derivatives acting at this receptor. This article will review the development of 5-HT7R antagonists with an emphasis on selective antagonists, their structural requirements and ligand-receptor interactions, as well as the potential therapeutic opportunities surrounding 5-HT7R ligands.