Oxford Ionics is a quantum computing company founded in 2019 by Dr Chris Ballance and Dr Tom Harty, who met as undergraduates at the University of Oxford. It develops trapped-ion quantum computers that use a patented Electronic Qubit Control system to manipulate qubits with electronics on a silicon chip instead of lasers. Its processors can be produced in standard semiconductor fabrication plants. Its quantum computers are field upgradeable, compact enough to fit within a standard double server rack, and integrate with computing stacks such as AWS and NVIDIA.

The company's roadmap targets 16-64 qubit systems at 99.99% fidelity in 2025, 256+ qubit devices in 2026 and 10,000+ qubit systems in 2027. In July 2024 it reported the highest-performing quantum chip in the world, with single-qubit and two-qubit gate fidelity records achieved without error correction, followed in September 2024 by a state preparation and measurement record of 99.9993%. Its Mini-Q portable quantum computer is being built with Infineon Technologies for Germany's Cyberagentur as part of a €35M investment, and is the first mobile variant of its line. A quantum computer called QUARTET was installed at the UK National Quantum Computing Centre's Harwell data centre in August 2025, under a £6M contract awarded in February 2024.

Oxford Ionics has worked with Airbus and simulation software developer Quanscient on quantum computational fluid dynamics, was selected by the UK Quantum Missions pilot in March 2025 and by DARPA for its Quantum Benchmarking Initiative in April 2025, and partnered with Iceberg Quantum on qLDPC-based fault-tolerant architecture in July 2025. It opened its first US office in Boulder, Colorado in 2024 and a 30,000 square foot global headquarters in Oxford in March 2025. Its team spans the UK, US and Switzerland. IonQ agreed to acquire the company in June 2025 in a deal valued at about $1.075 billion, and the acquisition was completed in September 2025.