Extant literature on mathematics instruction in the ICT environment has reported its potential and the role of teachers. However, there is a paucity of literature regarding how teachers specifically organize the use of ICT instruments in instruction and distribute authority with and for students during mathematical discussion. This study analyzes the instructional organization and practices in Korea that promote students’ inquiry-based learning in an ICT environment by using the framework of instrumental orchestration. This framework considers how teachers utilize various artefacts and adjust teaching to promote students’ learning. In addition, the study examines how teachers distribute authority in the classroom to promote students’ inquiry activities. The study reports different types of instrumental orchestration and compares the distribution of authority in four teachers’ classes. The study also discusses implications for inquiry-based learning in ICT environments.