We apply semi-structured interviews to conceptualise perceptions of global citizenship among teachers at an international school and teachers at a local public school in Israel, revealing discrepancies between theory and practice in global citizenship education (GCE). We find that teachers perceive global citizenship differently along three major axes: boundaries of global citizenship, practical aspects of GCE, and through the effect of Israel's context. This study offers a comparative perspective that discerns the differing impacts of school context and student background on teacher perceptions at different kinds of schools and highlights the importance of teacher agency in GCE.