The purposes of this investigation were to develop and validate a comprehensive assessment instrument to measure academic self-regulation as a personal trait. The instrument was predicated upon an evidence-based conceptual framework of academic self-regulation which described the interactions between cognitive, motivational, volitional, and environmental variables and learners' activating purposeful goal oriented actions. Seven separate studies which included over 1000 undergraduate and graduate students at a large mid-Atlantic university provided reliability and validity evidence for this instrument. Data analysis included Rasch analysis, item response and item analysis, exploratory factor analysis, correlation analysis comparing the developed instrument with a version of an instrument frequently used in studies of academic self-regulation, multiple regression analysis predicting the scales of the frequently used instrument through the developed instrument, item-total correlations, and Cronbach's alpha for each scale and for the entire questionnaire. Findings included evidence that the model accurately represented academic self-regulation; that the developed instrument was reliable; that the instrument had excellent content, structural, substantive, and criterion validity; and that the instrument appeared to yield useful information about the degree to which learners engaged academic self-regulation skills. While additional validation studies are warranted, three potential applications of this instrument are: to investigate academic self-regulation variables; to design learning environments to promote academic self-regulation; and to assess and assist individual learners develop academic self-regulation skills and dispositions.