The advancement of human civilization has been closely tied to our growing ability to harness extreme environments. Additive manufacturing (AM), also known as three-dimensional (3D) printing, has brought about a revolutionary transformation in the fabrication of materials designed for such conditions. This special issue aims to highlight the transformative role of additive manufacturing in enabling high-performance and multifunctional materials—including alloys, polymers, ceramics, and composites—for applications in extreme temperature, radiation, corrosion, pressure, and mechanical stress environments. We invite contributions that explore, but are not limited to, the following topics:

• Design of 3D printable materials for extreme environments;
• Assessment of the capability of traditional materials for extreme environments in AM;
• AM of materials for extreme environments with enhanced performance;
• Fabrication of multi-material components for extreme environments by AM;
• Modelling and simulation of AM processed materials in extreme environments.