Purpose: Principals commonly struggle to have effective conversations about staff performance issues, tending to tolerate, protect, and work around such issues rather than effectively addressing them. This article evaluates principals’ effectiveness in having "difficult" conversations with parents and with teachers. Research Methodology: This article reports a partial replication of a previous study in which the theoretical framework of Argyris and Schön was used to analyze the interpersonal effectiveness of newly appointed principals in a conversation with a parent. In this study, the results of these same 27 principals are compared with those gained in a second difficult conversation, this time with a teacher. The conversations were standardized by limiting each to 7 minutes and using the same actor to play the part of the parent complainant and teacher. Findings: Overall, principals demonstrated consistently low to moderate levels of skill across the two conversations. Typically, principals were more skilled in advocating their own position than in deeply inquiring into and checking their understanding of the views of the parent or teacher. Implications: Leaders need the confidence and skills to engage in productive and respectful conversations about the quality of teaching and learning to be effective instructional leaders. Consistent low to moderate capabilities demonstrated in these conversations suggest that educational improvement demands targeted professional learning for leaders. This research contributes to a research and development agenda by identifying the patterns of reasoning and action that constrain and facilitate more effective interpersonal capabilities.