Abstract: Growing concerns of maintaining the best talent have contributed to the rising number of idiosyncratic deals (i-deals) at the workplace. I-deals refer to the personalised work arrangements between employees and their employers where the terms benefit both parties. Despite the acknowledgment that supervisors are key in creating i-deals, research to date has overlooked their role. Drawing on prosocial motives and social learning theory, we explore an overall model of what triggers employee flexibility i-deals and the consequences of such i-deals on employee outcomes. In so doing, we explore one of the key yet untested assumptions of i-deals theory: that they are intended to be mutually beneficial. We investigate our model with matched supervisor – employee data (n = 186) collected in El Salvador and Chile. Findings reveal that there is a positive association between supervisors’ prosocial motives and employees’ flexibility i-deals. Moreover, prosocial motives of supervisors trickle-down and shape employees’ functioning at work (i.e., work performance and deviant behaviours) and lead them to be more prosocially motivated through employees’ flexibility i-deals.