<p>Teachers’ emotions both shape and are shaped by their teaching and interactions with others in their educational setting. Researchers have called for more attention to the emotional dimension of teachers’ work, specifically in the context of professional learning for changing practice. In this study, six Australian secondary mathematics teachers at a large low-SES multi-ethnic government school experimented with non-traditional algebra learning tasks and problem-solving pedagogies to engage their Year 8 students. Drawing on a social–psychological theoretical framing of teacher emotions in the context of educational change, we share findings on the teachers’ emotional experiences through their expressions in collective and individual settings. Initially focussing on situational demands in appraisals about their changes in practice, the teachers increasingly evidenced identity talk that brought to light an emerging collective narrative that their experimenting benefited their students yet cost them emotionally. The openness of experienced and leading teachers in a collective setting, and affirmation by colleagues to sharing emotionally charged experiences, was found to stimulate identity talk. In both collective and individual settings, the teachers were more likely to express positive valence with explicit emotion labels but to imply negative valence with descriptions or ambiguous emotion words. Possible implications for school leaders and facilitators of teacher professional learning are discussed.</p>