In this work, we developed experimental approaches on indium co‐doped ZnO‐based ceramics from the synthesis to the characterizations and analysis of physical features in the aim to achieve the formation of highly conducting ceramics with controlled nonlinearity. Different doping molar ratios of indium were used and the synthesis of the ceramics was realized by the conventional solid‐state reaction method which was then followed by a sintering under air (A), nitrogen (N), or a mixture of nitrogen and carbon monoxide (NC) atmosphere with different reduction capabilities. The structure, morphology, electrical investigations, and the electronic transport analysis were conducted on the different ZnO co‐doped ceramics as functions of the indium incorporation and the used sintering atmosphere, A, N, or NC. Suitable indium doping of 0.3 mol% and the use of highly reducing sintering atmosphere (NC) ensure the formation of ZnO‐based ceramics with an electrical conductivity up to (103 S/cm) and a quasi‐linear behavior on the electrical characteristic I–V. We discussed the obtained performances by correlating the charge transport with the microstructure of the ceramics, the composition, and the structure of grain boundaries as well as the solubility of indium in the host ZnO ceramic grains.