GERDA (GERmanium Detector Array) is an experiment conducted at the underground laboratory of LNGS (Laboratori Nazionali del Gran Sasso) to search for neutrinoless double beta decay in Ge76. It uses enriched high-purity germanium diodes both as the sources of the decay and as the detectors. The unparalleled energy resolution of germanium detectors, among other features of the experiment, has placed GERDA as one of the most competitive experiments looking for this decay. In this poster, we present the details of the energy calibration performed in GERDA, including those on the calibration source and its deployment, the energy scale calibration, as well as the energy resolution measurement. The estimations of the systematic uncertainties on the energy scale and resolution are also discussed.