Magnetic resonance spectroscopy (MRS) data for a series of GABA phantoms specifically  designed to provide ground truth data for GABA quantification based on MRS data. The spectra were obtained using the WIP Siemens implementation svs-edit of the common edited spectroscopy MEGAPRESS sequence on a 3T Siemens Magnetom Skyra system installed in the Clinical Imaging Unit at Swansea University (UK).