This study contributes to understanding sources of gender differential item functioning (DIF) on mathematics tests. This study focused on identifying sources of DIF and differential bundle functioning for boys and girls on the British Columbia Principles of Mathematics Exam (Grade 12) using a confirmatory SIBTEST approach based on a multidimensional model. Problem solving as a content area was confirmed as a source of gender DIF in favor of boys when the item is presented in the form of a story problem or when the problems are noncontext specific. Patterns and relations content areas produced a mixture of confirmed sources of DIF, with some subtopics favoring the girls and some favoring the boys. In contrast to what might be expected given the findings of previous gender DIF research, this study did not find geometry to be a source of gender DIF. All of the higher cognitive level items favored boys. High levels of DIF were detected in favor of girls on the bundle of computation items in which no equations were provided in the question.