The article describes a new magnetoencephalography (MEG) system that can be worn like a helmet, allowing subjects to move freely during scanning. This system integrates optically pumped magnetometers (OPMs) with a nulling system to reduce background magnetic fields. OPMs, which do not rely on superconducting technology, are integrated into a 3D-printed scanner-cast that fits snugly on the scalp, enabling high-resolution and high-fidelity electrophysiological measurements even with large head movements. The system demonstrates successful measurement of brain activity during natural movements such as nodding, stretching, and playing a ball game, with results comparable to those from conventional cryogenic MEG systems. The authors highlight the potential of this wearable MEG system for studying brain function in various subjects, including infants, children, and patients with movement disorders, and for investigating naturalistic tasks that require free movement.The article describes a new magnetoencephalography (MEG) system that can be worn like a helmet, allowing subjects to move freely during scanning. This system integrates optically pumped magnetometers (OPMs) with a nulling system to reduce background magnetic fields. OPMs, which do not rely on superconducting technology, are integrated into a 3D-printed scanner-cast that fits snugly on the scalp, enabling high-resolution and high-fidelity electrophysiological measurements even with large head movements. The system demonstrates successful measurement of brain activity during natural movements such as nodding, stretching, and playing a ball game, with results comparable to those from conventional cryogenic MEG systems. The authors highlight the potential of this wearable MEG system for studying brain function in various subjects, including infants, children, and patients with movement disorders, and for investigating naturalistic tasks that require free movement.