Accountability is an imperative element of organizations that Human Resource Management establishes as a behavior guideline. It encourages employees to be responsible for decisions and actions they took. Employing Social Cognitive theory, this study aims to investigate the mechanism of how formalization influences employee accountability. We hypothesize that this relationship is mediated by managerial monitoring behavior and perceived competence. Data was collected from 331 employees of a government agency in Indonesia. Structural equation modelling analysis reveals that (1) formalization directly and indirectly influences employee accountability, and its direct effect is higher than its indirect effect, suggesting the importance of formalization system in Human Resource Management; (2) the contribution of perceived competence as a mediator between formalization and employee accountability is higher than the contribution of managerial monitoring behavior, suggesting the importance of micro-foundations of Human Resource research; (3) the relationship between formalization and employee accountability was serially mediated by managerial monitoring behavior, which was preceded by managerial monitoring behavior for task performance and continued by managerial monitoring behavior for interpersonal facilitation This study contributes to international Human Resource Management literature by explaining the mechanism by which formalization affect accountability.