<p>This study investigates how novice secondary mathematics teachers notice students’ functional thinking and examines the relationship between their mathematical task performance (MTP) with their noticing skills. A total of 86 novice secondary mathematics teachers in China participated in the study by completing a questionnaire that assessed their MTP and professional noticing skills in analyzing written artifacts of students’ solutions about linear functions. Thematic analysis was used to code and interpret the noticing responses. The findings reveal that novice mathematics teachers demonstrate relatively strong attending and responding skills, but face challenges in interpreting students’ functional thinking. Furthermore, teachers with medium-level MTP exhibited stronger attending and responding skills compared to their high-level peers, though the difference was not statistically significant, and performed significantly better than their low-level peers. Teachers with low-level MTP showed the weakest results across all noticing dimensions. The findings provide evidence-based insights into teachers’ professional noticing of students’ functional thinking and highlight how teachers’ MTP may influence their noticing practices.</p>