The purpose of the study was to examine gender differences in performance on multiple-choice mathematical ability test, administered within the context of high school graduation test that was designed to match eleventh grade curriculum. The transformed item difficulty (TID) was used to detect a gender related DIF. A random sample of 1400 eleventh graders in Kuala Lumpur was selected. In DIF indexes, females showed a statistically significant and consistent advantage over males on items involving algebra, whereas males showed a less consistent advantage on items involving geometry and measurement, number and computation, data analysis, and proportional reasoning. However it was concluded that gender differences in mathematics may well be linked to content.