Close to a decade ago Hong Kong completed the implementation of a New three-year Senior Secondary (NSS) curriculum by introducing the Hong Kong Diploma of (HKDSE) examination. Because mathematics is one of the core subjects intricately involved in this education reform, it is necessary to evaluate the connection between the Hong Kong S1 - S6 mathematics curriculum and the mathematics compulsory portion of the HKDSE examination. A curricular alignment study can provide insight to policymakers, students, teachers, and schools concerning agreement between the intended curriculum and the assessed curriculum. This research study adopted a combination of criteria from the Achieve's alignment protocol and Webb's alignment method to determine the alignment between the Hong Kong S1 - S6 mathematics curriculum and the mathematics compulsory part of the 2018 HKDSE examination. A panel of three mathematics educators identified the assessment item/learning objective match, classified the content centrality value of each match, and identified the Depth of Knowledge of each assessment item. The alignment results indicate a wide range from no to strong indication of alignment between the Hong Kong S1 - S6 mathematics curriculum standards and the 2018 HKDSE examination. Areas of misalignment were found within the Measures, Shape and Space strand and the Data Handling strand of the Hong Kong S1 - S6 mathematics curriculum, where both show deficiencies in meeting the minimum benchmark for the categorical concurrence and the range of knowledge correspondence. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]