Low-emissive Transparent Conductive Oxide (TCO) coatings, such as Indium Tin Oxide (ITO) films, can be used to reduce radiative losses that affect Hybrid photovoltaic-thermal (PV-T) devices. This work shows the optical properties of ITO deposited by magnetron sputtering on a glass substrate with and without thermal heat treatment at different temperatures. All the analyses conducted include UV-VIS and infrared regions, up to 20 μm.