A dental glass ionomer cement composition comprises:(a) 5 to 100 parts by weight of a polymer of an .alpha.-.beta. unsaturated carboxylic acid having a weight average molecular weight of 5,000 to 40,000,(b) 5 to 100 parts by weight of a fluoroaluminosilicate glass powder having an average particle size of 0.02 to 10 .mu.m and a specific gravity of 2.4 to 4.0 and capable of reacting with said "polymer of an .alpha.-.beta. unsaturated carboxylic acid having a weight average molecular weight of 5,000 to 40,000",(c) 5 to 100 parts by weight of a polymerizable unsaturated organic compound having at least one CH.sub.2 .dbd.C(R1)--COO--group wherein R1=H or CH.sub.3,(d) 0.01 to 5 parts by weight of a polymerization catalyst,(e) 2 to 50 parts by weight of water,(f) 0.01 to 20 parts by weight of a surface active agent, and(g) 0.01 to 5 parts by weight of a reducing agent, and optionally h. 0 to 50 parts by weight of an inorganic filler having an average particle size of 0.02 to 10 .mu.m and undergoing no reaction with said "polymer of an .alpha.-.beta. unsaturated carboxylic acid having a weight average molecular weight of 5,000 to 40,000".