Idiosyncratic deals (i-deals) are individualized employment arrangements negotiated between organizations and particular employees (“i-dealers”). Most prior research has focused on the two parties to the i-deal, but in the current work, we focus on the co-workers of i-dealers who are often affected by the i-deals of others in ways that have additional and sometimes unexpected implications for organizations. We present a theoretically grounded framework that integrates cognitive, affective, and contextual processes to better understand when and why co-workers develop positive, neutral, or negative reactions to such arrangements. We predict that a range of reactions can occur, and may vary in valence (positive, neutral, or no reaction, or negative), degree of activation (active or passive), and target of the reaction (the organization, the i-dealer, or self). The nature of the reaction mirrors the emotions of the co-worker in response to self- and other-oriented cognitive appraisals of the i-deal by the co-worker. The nature of the reaction is also shaped by the consistency of the i-deal with the organization’s norms for differential treatment of employees. In the concluding section, we discuss future extensions and research implications of our model, and a number of potential managerial considerations that derive from our theorizing.