This study investigated university students' attitudes towards learning English vocabulary through collaborative group work (GW) versus individual work (IW) while performing vocabulary-focused tasks following reading comprehension. The second year, non-English major, Taiwanese students (N = 44) worked either in mixed ability groups of 3-4 or alone. The same students were exposed to the two treatments: classroom intervention was conducted with alternating sessions (one-week IW, one-week GW) for 12 weeks with accompanying tests of vocabulary learning. Attitude questionnaires (44 students) were administered before the classroom intervention and again after, together with interviews (24 students). Results showed that students increased in favourable attitude to IW more than to GW over the study period, even though their actual vocabulary learning improved more with GW. Nevertheless, by the end they did report GW as less stressful than IW and as providing better support and enabling more efficient work on the tasks, with greater likelihood of correct information being obtained. The findings suggest that enhancing students' vocabulary learning through GW was valuable despite student perceptions of it not being unambiguously favourable, and the use of GW in university English classes needs to be encouraged, albeit with continuity of group membership over time.