Quantum technologies have the potential to revolutionise science and society as early as the next five to ten years but require resources that are not mainstream today. CERN can be at the forefront of this revolution, setting up collaborations within the Member States, as well as international initiatives. Through such endeavours, we can work to develop new computing, detectors, and communications systems, in addition to advancing knowledge of quantum systems and fundamental physics. The Quantum Technology Initiative is based on more than two years of pilot collaborations and investigations — primarily in quantum computing — related to possible applications that are core to activities in high-energy physics (HEP). Over the past few years, knowledge and technologies have evolved considerably; dedicated support for research and development in quantum technologies has become part of national and international research agendas. The time has come for CERN to engage more formally with such activities. Thanks to its role in HEP and more broadly in European and international scientific research, CERN has compelling requirements for its future instruments and infrastructures, which represent very valuable application use cases. This puts CERN in a unique position to catalyse interests and investigations to act as a hub for innovation and knowledge creation and sharing, and to have a long-lasting impact on applying quantum technologies to high-energy physics (HEP) and beyond. The CERN Quantum Technology Initiative has defined a medium- and long-term roadmap and research programme in collaboration with the HEP and quantum-technology research communities. Together, we will establish joint research, educational and training activities, set up the supporting resource infrastructure, and provide dedicated mechanisms for exchange of both knowledge and technology.