The students' perception of how they are positioned by their teachers offer valuable insights into how teachers might engage students in the act of learning, construct themselves and acts in ways desirable to students, and how they might make the learning process a more enjoyable one for students. Teacher positioning is an important factor in developing the student mathematics identity. It is through positioning that a teacher communicates a set of rights, duties, and obligations that are linked to the position. In this study, we explore the relationships between students' perception of teacher positioning and student mathematics identity and how problem-solving flexibility mediates this relationship. The study employed a mixed-methods research design. A sample of 12 mathematics teachers responded to the Teachers' Perception of Mathematics Identity Survey while their corresponding students, with a total of 508 Grade 11 students responded to the Students' Perception of Teacher Positioning Survey, Student Mathematics Identity Scale, and Problem-Solving Flexibility Test. The correlational statistics and mediation analysis employing a structural equation model were used to investigate the relationships among the variables of the study. In-depth interviews of the teachers and focus group discussions with students were conducted and subjected to qualitative content analysis. Results of the mediation analysis showed that problem-solving flexibility partially mediated the relationship between students" perception of teacher positioning and student mathematics identity. Knowing that students" perception of how they are positioned by their teachers influences students' problem-solving flexibility and student mathematics identity, mathematics instruction that promotes flexibility is encouraged.