Written communication is one of the main competences in language acquisition, not least foreign language learning. The onus to teach this skill to highly qualified future workers is on higher educational institutions (Dickson, 2009), as written discourse is pivotal in both academic and professional contexts (Whittaker & Llinares, 2011; Chaudron, Martín Úriz & Whittaker, 2005). Despite the myriad of free online tools available to edit and self-review texts, students seem to struggle with those rules which are different in their mother tongue (Futina, Fata & Fitrisia, 2016). In fact, lexical transfers and other grammatical errors are generally found in EFL academic writing (Bellés-Calvera & Bellés-Fortuño, 2018; Manzano Vázquez, 2014). At this point, corrective feedback has proven to be an intrinsic part of the writing process (Ferris, 2002) as it has traditionally been used by students to improve their communicative competence in the target language (Hyland, 1998). The aim of this paper is to present a comparative study in which students’ most common errors at B2 level will be analysed on the basis of gender in an online learning context since recent studies have revealed that female learners are better at second language acquisition than male learners (Larsen-Freeman & Long, 2014; Futina, Fata & Fitrisia, 2016). The sample for this study consisted of a group of 40 Psychology undergraduate students and the corpus compiled contains eighty compositions in total. To achieve the purpose of our study, those written contributions were corrected and analysed so as to check their progress over the course. To this end, students’ most common errors were classified into a number of categories, including spelling, organisation, wrong word choice, verb tense or word order, among others. Results indicated that first language (L1) interference played an important role in students’ inaccuracies, particularly at a lexico-grammatical level. Surprisingly, no significant gender-based differences could be observed in terms of written performance. The provision of corrective feedback should also be considered as it is intended to help students overcome persistent linguistic shortcomings. What language teachers may find profitable about this study may be linked to the identification of problematic areas in English as a Foreign Language (EFL) that need to be tackled in higher education, more specifically in the Psychology classroom. The current research could also shed some light on the set of corrective feedback strategies that seem to have a positive effect on students’ written performance and, thus, work in online learning environments.