Intertextuality is an important academic writing ability when using others’ ideas efficiently and is tanta- mount to failing in the fulfillment of the research part of MA programs if improperly utilized. This study was thus intended to delve into university teachers’ judgment of what they may count as proper or im- proper intertextuality and the reasons why students might deviate from the acceptable norms of intertex- tuality. To this end, four extracts of MA theses together with their original sources were presented to four university professors with different academic rankings. Through an interview, the four extracts were evaluated and their intertextual qualities were explained. The data analysis revealed that university pro- fessors assessed intertextualities as proper or improper inconsistently within two rounds of evaluation. Furthermore, they recounted cultural, social, educational, developmental, virtual and economic reasons for students’ deviating behaviors in the utilization of the resources available. As for the criteria of illegit- imate intertextuality, it was found that no signaling to the reader subject to the violation of the following conditions including specific domain knowledge, more than one sentence copied or paraphrased, mis- match between source and target, and the particular section of the thesis where borrowed ideas are to be used could lead to plagiarism. This study has implications for thesis writers, thesis raters, and EFL writing teachers which are discussed in the paper. پرونده مقاله