Pure and In‐doped ZnO particles with two morphologies: rods and platelets were synthesized using hydrothermal method and tested for gas sensing. The materials were characterized by X‐ray diffraction, scanning electron microscopy and Raman spectroscopy. Platelets were synthesized with zinc acetate and potassium hydroxide in a ratio 1:3, while rods were obtained for a ratio1:8. As‐synthesized particles do not exhibit any sensing response. The creation of oxygen vacancies, through thermal treatments under reducing atmosphere (Ar:H2), activate the sensing properties. The best sensitivity, upon exposure of CO and propane, was obtained on the In‐doped platelets with large ±(0001) surface area. The value of the contact barrier between particles after the thermal treatment is 164 µeV.