This volume contains papers presented at the 12th International Conference on Materials and Manufacturing Technologies (ICMMT 2021) was held online during April 23-26, 2021, which is expected to be held annually. The topics covered in the collection are in the major areas of materials science and materials processing technologies: nanomaterials, polymers and composites, materials for energy storage and electrotechnical application, technologies and materials for waste treatment, technologies of structural metals processing, building materials.