This thesis reports on a study of the transfer of mathematical knowledge by undergraduate chemistry students. Transfer in this research refers to the students’ ability to use mathematical concepts, previously experienced within a mathematics course, within chemistry contexts. A pilot study was undertaken with a sample of second-year undergraduate chemistry students in order to determine their ability to transfer mathematical knowledge from a mathematics context to a chemistry context. The results showed that, while certain students could transfer (i.e., answer mathematical items correctly in a mathematics context and then in a chemistry context), many students were unable to transfer due to insufficient mathematical knowledge. These results motivated the main study, in which students’ ability to transfer mathematical concepts was investigated and analysed in two respects. These were the degree to which transfer was present, and the degree to which a particular characteristic, namely students’ ability to correctly explain their mathematical reasoning, underpinned successful transfer. It was found that students who evidenced an ability to explain their reasoning in a mathematics context associated with transfer. An intervention programme was designed which focused on the development of student understanding of mathematical concepts, both in terms of symbolic actions and linking these symbolic actions with mathematical referents/objects. This intervention programme was informed by current mathematics-educational theories. The evaluation of the intervention programme involved determining students’ mathematical understanding, their ability to transfer, and their opinions as to its usefulness. While the majority of the students found the intervention programme beneficial, students’ competency in respect of linking mathematical actions with referents/objects varied over the different concepts studied. Students’ ability to transfer also varied from one concept to another. The systematic process adopted in this study, of both determining students’ ability to transfer and the factors influencing transfer, and using this information together with mathematics-educational theories in developing intervention programmes, is applicable to transfer studies across other disciplines.