This study aimed to investigate the attrition rate of EFL concrete and abstract vocabulary among continuing andnon-continuing Iranian female and male English language learners across different proficiency levels. Theywere students of a University who majored in different fields (between 20 and 25 years old). There was notreatment involved in this study, where the researcher compared two groups using the same variables. Hence,the design of the current study is an ex-post facto design. A 40-item vocabulary test, which varied across twoproficiency levels, was used to measure the rate of vocabulary attrition as the instrument of this research. Inthe two stages, after an interval of three months, the students were requested to take the same tests. The resultsrevealed that there was no significant difference between the EFL attrition rate of the abstract and concretenouns among the continuing students across different proficiency levels. However, this hypothesis was rejectedfor the non-continuing learners at intermediate and advanced proficiency levels.