An ink composition for additive manufacture of silica aerogel objects essentially consists of a gellable silica sol containing an admixture of 30 to 70 vol. % of a mesoporous silica powder in a base solvent. The mesoporous silica powder has a particle size range of 0.001 to 1 mm and a tap density of 30 to 200 kg/m3 and comprises at least 10% by weight of silica aerogel powder. The composition has a yield stress in the range of 30 to 3000 Pa and a viscosity of 5 to 150 Pa·s at a shear rate of 50 s-1. Furthermore, the composition has shear thinning properties defined as a reduction in viscosity by a factor between 10 and 103 for an increase in shear rate by a factor of 104 to 105. A method of additive manufacturing of a three-dimensional silica aerogel object by direct ink writing comprises providing such ink composition, forcing the same through a convergent nozzle, thereby forming a jet of the ink composition which is directed in such manner as to form a three-dimensional object by additive manufacturing. After initiating and carrying out gelation of the gellable silica sol constituting said object, a drying step yields the desired three-dimensional silica aerogel object.