The Mathematics Teacher Education Partnership (MTE-Partnership) seeks to transform secondary mathematics teacher preparation to ensure that candidates are prepared to support the success of their students in alignment with the Common Core State Standards. Organized by the Association of Public and Land-grant Universities (APLU), the MTE-Partnership includes 38 teams headed by an APLU institution along with at least one K-12 district and other partners. A set of Guiding Principles developed in the initial phase of the project builds on the premise that strong partnerships across mathematics departments, colleges of educations, and K-12 are necessary to making real progress. Incorporating these stakeholders, the project is currently developing interventions in five areas, which are informed by the Mathematics Education of Teachers II. This talk will provide a brief overview of the partnership and the important role played by mathematicians in its work.