This dataset contains spectra for 31 M_L≥3.5 earthquakes in the Sea of Marmara region and spectra for their empirical Green’s functions (EGFs), used for earthquake directivity analysis. The study area surrounds the Sea of Marmara, close to Istanbul metropolis, with longitudes from 27.3° to 29.35° and latitudes from 40.5° to 40.9°. The ground velocity spectra were calculated using Fourier transform for three-component S-wave segments. The event information was obtained from the seismicity catalog of Becker et al. (2023). Detailed information about the earthquake directivity analysis can be found in the related study.