An ink composition and luminescent nanostructure composite, and an electronic device including the luminescent nanostructure composite. The ink composition includes a plurality of titanium oxide particles, a plurality of luminescent nanostructures (e.g., quantum dots), a monomer including a carbon-carbon unsaturated bond, and optionally an organic solvent. The titanium oxide particles have an average size of greater than or equal to about 10 nm and less than or equal to about 900 nm, and the titanium oxide particles comprise an organosilane compound. The ink composition has a total solid content (TSC) of greater than or equal to about 90 wt %, and an amount of the titanium oxide particles in the ink composition is greater than or equal to about 1 wt % based on the total weight of the ink composition. The ink composition is configured to emit a first light.