This book contains the proceedings of ICTRS 2023, the 12th International Conference on Telecommunications and Remote Sensing, held in a hybrid format in Rhodes, Greece, in September 2023. ICTRS is an annual event that brings together researchers and practitioners interested in telecommunications, remote sensing, and their societal implications. The 7 full papers and 4 short papers were thoroughly reviewed and selected from the 24 qualified submissions. ICTRS 2023 addresses a large number of research areas and topics, such as: wireless telecommunications and networking; electromagnetic waves and fields; electronics and photonics; remote sensing and data interpretation; remote sensing and Internet-of-Things; and societal impact.