Gastrointestinal (GI) neuroendocrine tumors (NETs), for example, carcinoids, are rare neoplasms characterized by the production of bioactive markers, such as 5-HT and chromogranin A. With the exception of surgery, there are limited curative and palliative treatments available for this type of tumor. Therefore, there is a great need to develop new pharmacological strategies to reduce tumor burden and control symptoms in patients with metastatic carcinoid tumors and the carcinoid syndrome. In this review, several pathways thought to be involved in GI NET carcinogenesis are discussed, and novel approaches that are currently in development to target these pathways are highlighted.