The Unified International Technical Conference on Refractories (UNITECR) ended with a great success. 1,122 participants attended this largest refractory world conference. The Scientific Committee, chaired by Prof. Dr. Christos G. Aneziris ensured high quality and diversity and ultimately selected 219 speakers and 53 posters from the 330 submissions. The lectures were summarized in this volume “UNITECR 2023 Proceedings” on 894 pages. They are sorted according to the following topics: