Metal-oxide-metal capacitors based on CaCu3Ti4O12 (CCTO) thin films, grown by metal-organic chemical vapor deposition and presenting a “brick wall” morphology, have been fabricated and characterized. In these capacitors, the coexistence of two Maxwell–Wagner related phenomena, i.e., the internal barrier layer capacitor and the electrode polarization effects, has been demonstrated and modeled. The detailed description of the involved mechanisms is discussed. High reliability and reproducibility in capacitors based on CCTO thin films can be achieved when the phenomena are controlled. A remarkable high capacitance density (about 100 nF/mm2) has been obtained at room temperature in optimised processing.