Abstract The current diversity and inconsistency among published quadrupole moments calls for a thorough evaluation of the available data. In this work, a review of the ground-state Q-moments of the oxygen to calcium isotopes is presented, resulting in a revised database of 43 quadrupole moments. For every π(sd) isotope chain, the quadrupole moments are expressed relative to one reference isotope. This common reference rules out the existing arbitrariness and provides a reliable basis for future measurements and theoretical studies. In addition, the evaluated quadrupole-moment values are compared to shell-model calculations, obtained with different effective interactions in the sd and sdpf model spaces and using the standard effective charges ep=1.3e and en=0.5e. The discrepancy between theory and experiment, observed for particular isotopes and isotope chains, calls for further fundamental research.