The main objective of this work is to know the perception of the undergraduate and master students of the three Galician universities about the plagiarism commission and check the relationship between it and the citation of documentary sources as a criterion for the evaluation of academics works by teachers of the different knowledge areas. The sample is made up of 8.943 students, with an approximate average age of 21 years, approximately 66% of women and from all knowledge areas. To collect the information, the Questionnaire for the Detection of Coincidences in Academic Works (CUDECO) is used. The data indicates that students have a lower predisposition to commit plagiarism in the event that teachers take action on it in the evaluation process. In conclusion, it is possible to establish a greater need for research about the characteristics of evaluation systems and, consequently, also about the characteristics of the teaching-learning process.