Psychometric properties of 24 items from the fifth grade Early Childhood Longitudinal Study-Kindergarten Cohort Mathematics Teacher Questionnaire were investigated in a sample of 5,181 participants. These items asked teachers to report how often they had their classroom students engage in different mathematics content, skills and instructional practices. Exploratory factor analyses were employed to evaluate the underlying factor structure of the selected items. Results suggest that these items effectively measure three distinct latent constructs that are specific to mathematics instruction: Instructional Practices for Teaching Mathematics, Developing Number Sense, and Beyond Number Sense. These results support the use of this instrument as a guide for research and policy, or to inform teacher curriculum decisions.