The increasing destruction of natural environments worldwide favored more and more alien species’ dispersal, distancing people from nature and consequently from native species. We investigated undergrad students’ perception about alien and native Brazilian species evaluating classes of the first (freshmen) and last semesters (seniors) of four courses in environmental sciences in three institutions and assessed these students’ knowledge level in different aspects related to native and alien species. The 509 interviewees were able to identify Brazilian native species better than alien species. They also produced better identifications among taxonomic groups of mammals (either alien or native), native birds, and exotic fish compared to invertebrate species. Most students did not consider themselves well informed about the topic. We found an association between the courses/semesters attended and the level of knowledge of the students. Thus, we concluded that, on the one hand, the students demonstrated relevant knowledge about the native species but, on the other, presented deficiencies in invasive alien species’ knowledge. Therefore, we suggest the revision/restructuring of how the biological invasions theme is covered in the academic curricula of undergraduate courses in the environmental area.