The speech act of disagreement is an area that has received scant attention in the field of interlanguage pragmatics. However, in academic communication the strategies employed in this act of speech precede the development of an argument, a textual genre that is considered central to scholastic positioning. The less equitable the power relationship between the parties (between peers, between teacher and group of students, etc.), the stronger the illocutive intensity of this act. This study aims to investigate the strategies used in an unequal situation (student/lecturer) by Chinese learners of Spanish as a second language in order to perform the speech act of disagreement in their second language. Data relating to 149 Chinese university students were gathered by means of a pedagogical framework-based task in which they had to write an email to their lecturer expressing their disagreement. To identify their sociopragmatic knowledge in a digital environment and its adequacy in an academic Spanish context, the microstructure of their writings was examined for pragmatic moves related to politeness and level of directness. Our results suggest that the Chinese students analysed in the study did not adjust to an appropriate register or manner in academic Spanish.