The study was designed to examine the effect of concordancing and scaffolding in developing learners’ knowledge of lexical collocations. Four tests were administered on two groups of Vietnamese learners of English to assess their ability in three aspects: (1) to identify (mis) collocations, (2) to provide answers with suggested options, and (3) to provide their own correction. Regarding the students’ ability to identify (mis) collocations and to provide answers with suggested options, the study revealed that concordancing significantly improved their score while scaffolding had no considerable impact. Concerning the students’ ability to provide their own correction, both concordancing and scaffolding were found to have a significant effect on the students’ performance. The study therefore discusses the importance of introducing a concordancer to promote learners’ independence in learning collocations. Scaffolding is also argued to be equally important especially when a concordancer is first introduced to students. Concordancing should be considered as a long-term task for learners in their development of collocation knowledge while scaffolding is temporary in its nature. Both concordancing and scaffolding can therefore be regarded as co-supporters in helping learners eventually take charge of learning collocations by themselves.