IWSM-MENSURA is the premier international conference on software measurement. Over the past three decades, the conference has built its reputation by attracting leading-edge researchers, leaders, and innovators with talks, tutorials, and discussions. The main goal is to share experiences, challenges, and solution approaches to facilitate technology transfers from best measurement and estimation-related practices developed by researchers and world industry experts. IWSMMENSURA is one of the pioneer conferences in attracting industry participation, with each year 5060% of its participants from the industry, either as speakers or as attendees. Therefore, IWSMMENSURA is quite unique in its rich discussions on the applicability of theoretical measurement research in the field. This edition confirms the IWSM-MENSURA tradition proposals from experienced industry practitioners and researchers on the state-of-the-art and the future of Information Technology cost estimation and control. We received twenty-nine submissions: eighteen as full papers, four as short papers, one as a discussion paper, and six as industry presentations. Submissions underwent a thorough review with each submission receiving feedback from at least four expert reviewers. Following extensive discussion amongst the reviewers and chairs, ten of them were accepted as full papers, two as short papers; five as industry presentations and one as a discussion presentation. The contributions deal with several interesting aspects such as functional size measurement, software quality, software metrics and measurement, empirical studies, effort estimation. The accepted contributions together with the keynote speeches constitute a stimulating program providing many new ideas and insights and suggesting new future research. We want to thank all the authors of the submitted papers and the program committee members who provided extensive and constructive feedback to the authors. We would also like to thank the IWSMMENSURA 2023 organization committee, in particular Luigi Buglione and Filippo De Carli, for helping us deal with all the logistics involved in running the event and Alain Abran for his suggestions and support along all the steps of the program preparation. Furthermore, our thanks go to Görkem Kılınç Soylu and Hüseyin Ünlü for all their work in the preparation of the conference proceedings.