Abstract The present study compared the compressive, tensile and flexural strengths of 26 commercial glass ionomer cements, which were evaluated 24 h after the beginning of the setting reaction. In order to give a global estimation of their overall strength, a coefficient was attributed to each glass ionomer cement. This strength coefficient provided a ranking of the tested materials. The highest scores were obtained by the restorative glass ionomers; however, these materials exhibited lower mechanical properties than the more classic restorative materials such as amalgams or composites. The results also showed a large scattering of the mechanical properties among the luting and lining glass ionomer cements. The creep behavior of the glass ionomer cements was also investigated.