This study examines four of the most commonly-used core mathematics curricula in the USA for evidence of support for research-based instructional strategies for mathematics vocabulary in first and second grade. Content analyses of the teachers' editions of two units for each grade level were analyzed per curriculum (n = 16). Statistically significant differences among curricula were found for number of target words (range 6-51 per unit), level of difficulty of terms (basic to technical), and number of support strategies per word. Multiple means of representation varied in terms of verbal and non-verbal strategies for target terms. These differences indicate children are experiencing substantially different mathematics vocabulary learning opportunities, which may impact later mathematics achievement. Implications for practice, curriculum development, and future research are addressed.