<p>Despite extensive research on academic procrastination, there is limited evidence on its construct and validity measures in EFL settings, particularly within the Iranian context. The current study aimed to investigate the construct and validity measures of academic procrastination among Iranian EFL learners, and justify necessity of context-specific instrumentation. In light of a sequential Mixed-Methods research design and in an attempt to explore both the context-specific nature and validity measures of the construct EFL-related procrastination both qualitative and quantitative data were employed to adapt and customize a scale based on Tuckman Procrastination Scale (1991) and the Procrastination Assessment Scale for Students (PASS) (1984). To do so, 414 Iranian English language university students attended a pilot phase of the study of which 150 responded a semi-structured interview and 209 contribute to the collection of quantitative phase of validation. The analyses led to the adaptation and development of a valid and reliable measure called Procrastination Scale for Iranian Academic Setting (PSIAS) characterized by nine context- and culture-specific components that holistically produce a pattern of matrix in which each component enjoy unique psychometric characteristics underscoring significant patterns in procrastination behaviors and attitudes across different academic tasks, recommending insights into the underlying causes of procrastination in Iranian EFL students. The findings contribute to the literature and pedagogy by presenting a valid and reliable scale for measuring context-specific academic procrastination on one hand but leave the space open for future research to address procrastination in language pedagogical settings.</p>