IEEE Transactions on Microwave Theory and Techniques (T-MTT) is a monthly peer-reviewed scientific journal with a focus on that part of engineering and theory associated with microwave/millimeter-wave technology and components, electronic devices, guided wave structures and theory, electromagnetic theory, and Radio Frequency Hybrid and Monolithic Integrated Circuits, including mixed-signal circuits, from a few MHz to THz.

T-MTT is published by the IEEE Microwave Theory and Techniques Society.

T-MTT was established in 1953 as the Transactions of the IRE Professional Group on Microwave Theory and Techniques.

From 1955 T-MTT was published as the IRE Transactions on Microwave Theory and Techniques and was finally the current denomination since 1963.

The editors-in-chief is Almudena Suarez (University of Cantabria).