Maintenance in a manufacturing company is a key function for maintaining or restoring the functional condition of the production equipment and machinery and thus for maintaining the overall efficiency of the company. Because of this role, maintenance is often considered "sustainable". As a result of regulatory requirements as well as stakeholder demands, companies are under pressure to specify their sustainability strategies. However, due to a lack of knowledge about the sustainability potential of this function, the identification of clear objectives for sustainable maintenance is often neglected. Therefore, this paper presents a performance indicator system. 133 performance indicators in the three dimensions of sustainability (economic, environmental and social) were identified in a systematic literature review. In a qualitative content analysis and inductive categorisation, these were then assigned to 20 different categories. The hierarchical arrangement as well as the derivation of sustainable maintenance objectives from the corporate strategy enables companies to rank the performance indicators with the help of AHP (Analytic Hierarchy Process), a tool of MCDM (Multi Criteria Decision Making). This leads to a system of performance indicators based on a company's sustainability strategy, which strengthens the focus on sustainability in maintenance functions.