Purpose: The purpose of this study was to ascertain the relationship between EFL teachers' perception of the intended and unintended consequences of formative assessment (FA) decisions and their sense of self-efficacy and anxiety toward data-driven decision-making (DDDM). Design/methodology/approach: A correlational research design and correlational/regression analysis was utilized to conduct this study. In addition, a thematic analysis was conducted of participants' responses to the open-ended questions. Findings: Descriptive statistics suggest that most EFL teachers perceived both intended and unintended consequential validity of their FA decisions with a moderate level of DDDM self-efficacy and a low level of anxiety. The results of the correlational analysis indicated a strong positive relationship indicating that those with higher teachers' perceptions of consequential validity of formative assessment (TPCVFA) scores tended to report higher DDDM efficacy. The results of the correlational analysis also indicated that a significant relationship did not exist between TPCVFA scores and DDDM anxiety. Finally, multiple regression analyses revealed that TPCVFA was a significant predictor of DDDM efficacy; however, TPCVFA was not a significant predictor of DDDM anxiety. Originality/value: Data collected from 114 Iranian EFL teachers using the Data-Driven Decision-Making Efficacy and Anxiety Inventory (3D-MEA, Dunn et al. 2013a) and the TPCVFA questionnaire, which was self-developed and validated for the current study.