Helpful students in the university play an important role in the learning process. In addition to disseminating knowledge within the classroom, they are a central element of motivation for those students who need more support. Current research in this topic has especially focused on the students' motivations and attitudes towards solidarity as a general ethical concept. However, despite its importance, less attention has been paid to the specific study of the solidarity inside the classroom. In this research, we especially focus on the personal traits that represent helpful students within the university's classrooms and the role that homophily plays in the establishment of these supportive relationships. On this basis, in this research we try to contribute to this area by answering two main questions: what personal traits, if any, characterize the most helpful students? And, on the other hand, what characteristics, if any, do helpful students share with the students to whom they provide academic support? By addressing a sample of students of the bachelor's degree of Business Administration at Universitat Politècnica de València in Spain and by means of Social Network Analysis techniques, this research provide evidence that most helpful students possess specific personal and behavioural traits. In addition, they also develop preferential supportive behaviours toward certain students with whom they share diverse characteristics. These results may have relevant consequences for the educational community. In this sense the results help lecturers to broaden their knowledge about the behaviour of students at university, allowing a better organisation of working groups and teaching activities.