The International Conference on Optical Fiber Sensors (OFS), established in 1983, is acknowledged as the world’s leading conference on all topics related to photonic sensing technologies. OFS provides a forum for reporting and exchanging ideas on the latest advances in research and development on fiber-optic and photonic sensing. It has also contributed significantly to industrialization and standardization of the related devices and systems for field deployment. The next 27th OFS conference, OFS-27, will be held in scenic and beautiful Alexandria, Virginia from June 7-11, 2021. It will offer plenary and invited talks, contributed oral and poster presentations, workshops, and exhibitions of commercial products. Social and cultural events will also take place to foster networking among the participants in a friendly setting.