Effective teachers are characterized not only by pedagogical abilities and subject area mastery, but also by interpersonal skills. Using the Tacit Knowledge Inventory for High School Teachers (TKI-HS) – a situational judgement test consisting of 11 challenging interpersonal scenarios – this study compared how experienced teachers in England (n=108), Ireland (n=45) and Russia (n=492) rated seven possible response options for each scenario, to examine the extent to which the concept of “skilled interpersonal behavior” varies across cultures. The results indicate that judgments of “bad” responses are more similar across these three cultures, whereas there seems to be less agreement about what constitutes a “good” response. The importance of teachers’ tacit knowledge and how it varies across cultural contexts are discussed.