Malonic acid reacts with the superacidic solutions XF/MF5 (X = H, D; M = As, Sb) to form their corresponding salts [(OH)2CCH2C(O)OH][MF6] and [(OH)2CCH2C(OH)2][MF6]2. The hexafluoridometalates of the mono‐ and diprotonated malonic acid have been characterized by vibrational spectroscopy and single‐crystal X‐ray structure analyses. Monoprotonated malonic acid, [(OH)2CCH2C(O)OH][AsF6], crystallizes in the orthorhombic space group Pbca with eight formula units per unit cell: a = 9.6739(4) Å, b = 11.8355(5) Å, c = 13.9826(6) Å, and diprotonated malonic acid, [(OH)2CCH2C(OH)2][AsF6]2, crystallizes in the monoclinic space group P21/n with four formula units per unit cell: a = 7.3348(2) Å, b = 9.8437(3) Å, c = 16.6903(6) Å, β = 97.818(3)°. The experimental data are compared to quantum chemical calculations at the MP2/aug‐cc‐pVTZ‐level of theory for the free cations [(OH)2CCH2C(O)OH]+ and [(OH)2CCH2C(OH)2]2+. A six‐membered ring‐like structure containing an intramolecular hydrogen bond was found for the monoprotonated species of malonic acid.