This article focuses on the process affecting interpersonal trust in the workflow of organizations. We propose a dynamic model which highlights the impact of interpersonal communicative action in ongoing task negotiations in trust formation among organization members. According to our model, individuals approach initial negotiations with a baseline of trust in their organization which influences their initial level of cooperativeness and assertiveness when engaging in interpersonal task negotiations. Individuals' levels of cooperativeness and assertiveness then influences their communicative action (i.e., information acquisition, selection, and transmission), which, in turn, impacts the amount of trust these individuals perceive toward their counterpart (i.e., interpersonal trust). Finally, interpersonal trust impacts trust in the organization as a whole, at which point new tasks build on the previous cycle of negotiation and trust formation. We conclude by highlighting the conceptual contribution of the paper and its implications for both future research and organizational practices related to trust formation and workflow coordination.