Dendritic cells (DCs) are potent antigen-presenting cells endowed with the unique ability to initiate adaptive immune responses upon inflammation. Inflammatory processes are often associated with an increased production of serotonin, which operates by activating specific receptors. However, the functional role of serotonin receptors in regulation of DC functions is poorly understood. Here we demonstrate that expression of serotonin receptor 5-HT7 (5-HT7R) as well as its down-stream effector Cdc42 is upregulated in DCs upon maturation. While DC maturation was independent of 5-HT7R, receptor stimulation affected DC morphology via Cdc42-mediated signaling. In addition, basal activity of 5-HT7R was required for the proper expression of the chemokine receptor CCR7, which is a key factor to control DC migration. Consistently, we observed that 5-HT7R enhances chemotactic motility of DCs in vitro by modulating their directionality and migration velocity. Accordingly, migration of DCs in murine colon explants was abolished after pharmacological receptor blockade. Our results indicate a critical role of 5-HT7R/Cdc42-mediated signaling in regulation of DC morphology and motility, suggesting 5-HT7R as a novel target for treatment of a variety of inflammatory and immune disorders.