An increasing number of manufacturing firms are developing new business models to improve sustainability in the face of growing environmental and social challenges. Product-service systems (PSS) are regarded as promising sustainable business models with significant potential to synergise economic, environmental and social value, together termed ‘sustainable value’. This research investigates ways in which manufacturing firms can identify opportunities for sustainable value creation in PSS business models. The research aims to make theoretical and practical contributions to the fields of sustainable business models, sustainable PSS and sustainable value. The research adopts a qualitative theory building approach, in which theory can be transformed into practice. It involves eight case studies and one focus group formed of manufacturers who provide PSS solutions. A practical-research tool, the Sustainable Value Analysis Tool, is developed to collect data and to provide business support. The key research findings and contributions to theory and practice are: · The research proposes a new PSS classification system based on the ownership of products and changes in ownership. This classification distinguishes the potential for sustainability of each PSS type more clearly than existing PSS classifications. · The research introduces a new concept, value uncaptured, and identifies four forms of this. The introduction of this concept provides a novel perspective of studying value exchange in business models. · The research identifies 26 sources of value uncaptured throughout the product life cycle. These can be used to help industrial practitioners to identify value uncaptured in a structured way. · The research proposed that the act of turning value uncaptured into value opportunities is an effective approach for improving sustainable value creation in business models. This has been empirically demonstrated. · The research proposes a model to understand how and where value uncaptured can be turned into value opportunities. This model comprises two mechanisms, two directions, and fourteen key tactics. The model improves theoretical understanding of the sustainable value creation system and can be applied in practice to help companies search for value opportunities in a systematic and strategic way. · The challenges of turning value opportunities into value are identified. The findings have been used to develop a framework for sustainable value creation in PSS business models. The proposed tool has been validated and used in workshops for purposes including research, consultancy, business education and university education. This research thus makes contributions to both academic knowledge and industrial practice.