The purpose of this research was to examine the effects of Inquiry-Based Learning (IBL) on the academic achievement, attitudes, and engagement of fifth-grade science students. Participants were from two science classes (N = 42). The experimental group received IBL instruction, while the control group received traditional instruction. Pretests and posttests were used to measure students' academic achievement during the 6-week study. The Science Attitudes Survey was administered to students pre-intervention and post-intervention to assess overall student attitudes about science. Student engagement was measured 3 days a week with a student engagement checklist. Fieldnotes recorded by the teacher-researcher were used for additional documentation. Students in the IBL group scored higher than students in the traditional group on the academic achievement posttest, although not statistically significant. Students who received IBL instruction showed a slight statistically insignificant decrease in their positive attitudes towards science but higher engagement as compared to students who received traditional instruction.