We assessed awareness of invasive alien species (IAS) among ornamental plant buyers and sellers across 44 nurseries in Bengaluru, using the Knowledge-Attitudes-Practices framework. Fewer than 30% of buyers and only 5% of sellers were familiar with IAS concepts, and over 75% of respondents did not know where the plants they bought or sold came from. When we explained the risks, 89% of buyers said they would choose safer alternatives and 57% of sellers said they would communicate risks to customers. The findings point to large knowledge gaps among urban nursery buyers and sellers, and to the role targeted education could play in bringing IAS management into urban planning and conservation.