The present study investigates the collocations of the first person plural possessive pronoun in order to identify L1 influence in Korean EFL learners' writing, in comparison with native English speakers’ writing. From a cognitive linguistic perspective, this learner corpus research focuses on the use of the first person pronoun OUR in English, which seems to be negatively transferred by somewhat peculiar usages of the Korean equivalent pronoun wuli. The contrastive interlanguage analysis first shows that Korean learners significantly overuse first person plural pronouns whereas they significantly underuse first person singular pronouns, compared to native English speakers. Second, it also indicates that the distribution of frequencies of the ‘OUR + noun’ collocations according to a classification based on the Sejong Corpus seems very similar in both corpora, and that the frequencies are likely to be dependent upon specific individual collocates. Third, Korean learners appear to particularly overuse six specific ‘OUR + noun’ collocations rather than ‘MY + noun’ collocations, which can be argued to be empirical evidence of L1 influence. The findings of the present study are expected to provide valuable implications to English language teaching in classroom in Korea.