Colorectal cancer (CRC) is the second leading cause of cancer-related deaths. Tumor angiogenesis plays a critical role in CRC metastasis, and hypoxia, which widely existed in the tumor mass, drives tumor angiogenesis. Sesamin, a phytochemical derived from sesame seeds, has been reported to inhibit tumor cell growth and metastasis, however, the role of sesamin in CRC angiogenesis and its underlying mechanism have not been investigated yet. Here, an in vitro tube formation assay and an in vivo angiogenesis assay were used to explore the role of sesamin in CRC angiogenesis. In this study, we found that sesamin significantly inhibited hypoxia-stimulated CRC angiogenesis in a dose-dependent manner in vitro. Moreover, oral intake of sesamin dramatically suppressed neovessel formation of matrigel plugs with CRC cells in nude mice. In mechanism, sesamin reduced the expression of VEGFA to inhibit hypoxia-induced CRC angiogenesis. In addition, sesamin inhibited the phosphorylation of IκBα and thus restrained NF-κB p65 to activate HIF-1α transcription under hypoxic conditions. Finally, our results indicated that sesamin inhibited hypoxia-induced CRC angiogenesis via the NF-κB/HIF-1α/VEGFA signaling pathway. Our study might provide a theoretical and experimental basis for the use of sesamin in the prevention and treatment of CRC.