There is gap in passing rates on the standardized science assessment between European American and Hispanic American students. The purpose of this study was to examine student performance in science and the closing of the achievement gap between European American and Hispanic American students based upon receipt of an inquiry or noninquiry instruction method. Guided by the theoretical framework of constructive learning, this quantitative ex post facto research design gathered data from 8 teachers who had already implemented 1 of the 2 methods of instruction. The teachers were chosen through purposive sampling based on previous observations of instructional method and were placed into 2 groups depending upon the type of instruction: inquiry or noninquiry. Descriptive statistics were used to determine mean differences and a 2-way analysis of variance was used to determine mean differences in science test scores between European American and Hispanic American students and between the instructional methods to which they had been exposed. Results found that the inquiry instructional method was related to a significant increase in mean scores for both ethnic groups, but the achievement gap between the two groups was not closed by the inquiry instruction method. This study can promote positive social change for students by informing the efforts of educational leaders and teachers to create professional development using inquiry instruction. Students may perform higher on standardized tests when they are allowed to explore science by asking questions and answering their own questions through the collection and analysis of data. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]