Research in the field of language attrition suggests that the use of a foreign language (FL) diminishes among language learners when it ceases to be actively employed. The present study aimed to investigate whether similar patterns of lexical attrition occurred among FL teachers, who were generally considered to possess a strong resistance to FL attrition. Specifically, this study sought to explore issues related to lexical attrition in the FL competence of English as a Foreign Language (EFL) teachers within Chinese educational contexts. A questionnaire consisting of 34 items and a self-report scale on vocabulary were administered to a sample of 105 EFL teachers from 43 junior high schools in China, accompanied by interviews with 10 participants. The results revealed that five factors, namely teachers' language contact, initial language proficiency, teachers' concerns about maintaining language proficiency, teachers' attitudes toward language learning, and artificially-intervened language use, accounted for 42% of the total variance and significantly influenced EFL teachers' lexical attrition. Notably, initial language proficiency and language contact emerged as the most influential predictors of lexical attrition among teachers. These findings indicated that EFL teachers' lexical attrition closely resembled that observed in other FL learner groups in China, which might have adverse implications for FL education in diverse ways. This research would provide valuable insights for improving the professional development of EFL teachers and enhancing FL education in such contexts.