The goal of the current study is to examine the impact of students' social economic status, ethnicity, and discipline infractions on their standardized test scores in Indiana, the USA. Data from this study extracted from Indiana Department of Education. ISTEP is a criterion-referenced standardized test. It consists of items that assess a student's performance with respect to particular criteria that was established by the Indiana State Board of Education. Criterion-referenced test scores help us to understand where a student stands in relation to the cut scores based Indiana Academic Standards in English/Language Arts and Mathematics. In fact, the application of ISTEP might be helpful for schools to identify their students' strengths and weaknesses in these content areas. By doing so, they take necessary steps to plan appropriate instruction for students' academic development. However, the Indiana Department of Education's statistical data show that there was a statistically significant achievement gap between students. Accordingly, the current study findings point out that the effects of SES and Race varied among groups. Specifically, African-American students with low SES status had lower scores on ISTEP than their white peers did. In addition, a chi-square analysis showed that disproportionality among African American students appeared to be striking. Findings and educational implications are discussed.