Blood vessel formation during vertebrate development relies on a process called angiogenesis and is essential for organ growth and tissue viability. In addition, angiogenesis leads to pathological blood vessel growth in diseases with tissue ischaemia, such as neovascular eye disease and cancer. Neuropilin 1 (NRP1) is a transmembrane protein that serves as a receptor for the VEGF₁₆₅ isoform of the vascular endothelial growth factor (VEGF) to enhance cell migration during angiogenesis via VEGF receptor 2 (VEGFR2), and it is also essential for VEGF-induced vascular permeability and arteriogenesis. In addition, NRP1 activation affects angiogenesis independently of VEGF signalling by activating the intracellular kinase ABL1. NRP1 also acts as a receptor for the class 3 semaphorin (SEMA3A) to regulate vessel maturation during tumour angiogenesis and vascular permeability in eye disease. In the present paper, we review current knowledge of NRP1 regulation during angiogenesis and vascular pathology.