Vocabulary plays a pivotal role in second language learning and development. Concordance-based methods are considered as new techniques for improving teaching materials and motivating learners to improve their language ability with authentic texts. To this end, the present study aims to enhance the effect of Innovative Concordancing Instruction (ICI) on vocabulary knowledge by integrating principled instructional approaches. The participants included 90 university students at undergraduate level in Islamic Azad University in Tehran, Iran. First, after giving a proficiency test, the students were divided into innovative concordancing, traditional concordancing and control group. The participants in both experimental groups were given eight-week vocabulary instruction, while no special vocabulary instruction was considered for the sample in the control group. Based on the results, ICI had both better immediate and delayed instructional effects on increasing receptive and productive knowledge although the students in instructional groups improved in terms of receptive and productive knowledge. The present study could present some implications for teaching vocabulary when designing vocabulary curricula and developing materials for EFL learners and teachers.
