Collocational competence is recognized to be integral to native-like L2 performance, and concordancing can be of assistance in gaining this competence. This study reports on an investigation into the effect of symmetrical and asymmetrical scaffolding on the collocational competence of Iranian intermediate learners of English in the context of concordancing. It also surveys the learners' attitudes towards the role of concordancing and scaffolding in learning L2 collocations. Immediate and delayed posttests were administered to examine the effects of the treatments given over 10 sessions on L2 collocations in the receptive and productive tasks. Results demonstrated that the three groups of participants who received the treatment tasks in the context of concordancing under symmetrical, asymmetrical, and no-scaffolding conditions, improved their knowledge of collocations significantly both in the receptive and productive tasks compared to the control group which had no access to concordancing and did not receive scaffolding. However, there was no significant difference among the performances of the concordancing groups either in the receptive or in the productive tasks. Moreover, learners expressed positive attitudes towards both concordancing and scaffolding.