The purpose of this study was to determine if middle school student scientific understanding could be predicted by the variables: standardized 5th grade score in science, standardized 5th grade score in mathematics, standardized 5th grade score in reading, student attitude towards science, socioeconomic status, gender, and ethnicity. An Attitude towards Science Survey (SATS) and a Survey of Scientific Understandings were administered to 116 middle school 8th grade students during the 2010-2011 school year. SES was a significant predictor of scientific understanding of middle school students since correlation results showed that only SES was a significant contributor to predicting scientific understanding of these students. Low SES students performed lower on the scientific understanding survey, on average, than high SES students. This study can be a source of information for teachers in low-income schools by recognizing potential areas of concern for low-income students in their science classrooms.