This study examines how professional noticing of student mathematical thinking evolves in the context of modeling and what is special about the context of modeling. Eight middle and secondary school teachers participated in this one-semester long study and received three training sessions on professional noticing. Teachers provided more substantial detail about the mathematical aspects of student strategies after participating in the training, and they benefited from conversations with colleagues scaffolded by three phases of professional noticing: attending to, interpreting, and responding to student thinking. Teachers also identified specific aspects of student thinking in the context of modeling, especially local conceptual development.