To determine the inherent components of language learners' capacity for metamemory maturity, the researchers drafted a metamemory maturity (MMM) questionnaire based on Hultsch et al.'s (Memory self-knowledge and self-efficacy in the aged, Springer-Verlag 65-92, 1988) model. The volunteer participants were a heterogeneous sample of 356 male and female English as a Foreign Language (EFL) teachers and student teachers with various age ranges, teaching experiences, and educational backgrounds. Through a series of factor analytic procedures and structural equation modeling, the final draft of the questionnaire with 30 binary Likert-scale items was validated. Statistics confirmed acceptable measures of internal consistency as well as convergent and discriminant validity. The newly designed MMM questionnaire consisted of three main components of memory strategy use (12 items), memory attentiveness (6 items), memory factual awareness (6 items), and a moderator component of confidence and affect (6 items). The researchers highlight the implications of this questionnaire to provide the teachers with an instrument to analyze the needs of EFL learners for metamemory enhancement strategies.