In this paper, I examine deficit talk, utterances that depict students and/or families based on their perceived deficits, in an equity-oriented professional development (PD) setting. Researchers often attribute deficit talk by mathematics teachers (MTs) to their biased beliefs and perceptions. From an interactional approach, namely conversation analysis and discursive psychology, I offer an alternative perspective on how deficit talk is produced in PD interactions. The analysis shows the rhetorical functions of deficit talk, which are designed for MTs to manage their accountability with a range of potential issues and to portray themselves as competent teachers. The analysis also reveals the action-performing nature of deficit talk (e.g., refusing a request) situated in the social interaction. To conclude, this paper suggests that mathematics teacher educators need to attend to the micropolitical nature of deficit talk and their co-participation in the production of deficit talk as they formulate ways to respond to deficit talk in PD interactions.