Maintenance is a key process contributing to sustainable manufacturing operations. According to this vision, recent scientific studies underline the need for indicators to assess maintenance sustainable performances. In the normative field, the EN 15341:2019 standard about Key Performance Indicators of the Maintenance Function was recently released covering all major aspects of maintenance and physical assets management, giving more emphasis to sustainability. Nevertheless, a complete set of indicators covering the environmental and social dimensions of maintenance sustainability under the sustainable manufacturing perspective is still missing. Therefore, in this paper the relevant factors to be considered for integrating the existing standard and to achieve a complete maintenance performance measurement system tackling sustainability are identified by analyzing the wider literature and normative frameworks about sustainable manufacturing performances. A validation in the industrial reality is identified as a next step to assess the factors’ applicability in terms of measurability.