Background: Researchers focused on developing therapeutic strategies for perfectionism given its well-established link to the onset and maintenance of several mental disorders. Meta-analytical findings provided support for the efficacy of cognitive behavioural (CB) approaches. However, most studies have focused on the efficacy of interventions, without analysing their efficiency. Aims: To explore the feasibility of a brief (five weekly sessions) CB group intervention focused on reducing perfectionistic concerns in Argentine students. We also aimed to identify participants who benefited from the intervention and to explore their differences with non-respondents. A third aim was to explore the potential merits of the intervention in a different cultural context as this is the first attempt to adapt an English-spoken protocol to the Spanish language. Method: A quasi-experimental design with two time points was used. Twenty-four out of 84 participants (mean age = 27.75 years, SD = 8.3) were classified as maladaptive perfectionists. Results: Paired t-tests and reliable change index comparisons revealed that most students (75%) statistically and clinically reduced their levels of perfectionistic concerns as well as their perfectionistic strivings. General distress, operationalized as anxious and depressive symptoms, was also decreased. Students who completed and responded to the intervention were more dysfunctional in academic and psychological measures at baseline than non-completers and non-improvers. Conclusions: Findings support the feasibility, preliminary efficacy and efficiency of this five weekly session intervention when applied to a sample of Argentine university students.