The purpose of this study was to explore the effect of a technology-supported learning environment utilizing an interactive whiteboard (IWB) and NuCalc graphing software compared to a traditional direct instruction-based environment on student achievement in graphs of quadratic functions and attitudes towards mathematics and technology. Sixty-five high school graduates attending cram schools (called dershane in Turkish) to study for the university entrance examination participated in the study. The significant interaction effect between time of testing and groups indicated that student performance across time of testing was dependent upon the presence or absence of the treatment. Comparisons suggest that although both experimental and control group students' performances increased from pre-test to post-test and then decreased from post-test to retention test, the rate of decrease was about the same and the rate of increase was different, with students showing a greater rate of increase in the experimental group. The results also revealed that the treatment had positively affected students' attitudes towards technology and mathematics. Moreover, students' reasoning and interpretation skills regarding graphs of quadratic functions were better in the experimental group as compared to those in the control group.