Purpose: This study aims to design and validate a conceptual and practical model of co-creation. Co-creation, to design collaborative new products, services and processes in contact with users, has become more and more important because organisations increasingly require multidisciplinary collaboration inside and outside the organisation to respond to challenges and create added value. Design/methodology/approach: This is a design and validation study, which uses mixed-methods, a reconstructive design and a semi-structured interview with a questionnaire as validation. The designed model is validated by 14 scholars and practitioners across fields. Findings:Designed is a conceptual and practical model, the four-dimensional Co-Creation-Wheel, which contains success factors for co-creation: 12 internal team factors plus 4 external conditions and a core. The validation study of this model, scientifically and as a practical instrument, supported the importance of the components of the model and suggested slight improvements. This resulted in a refinement of the first designed Co-Creation-Wheel. Research limitations/implications: Although restricted usefulness to large-scale structured innovation practices was expected, the instrument has a broader reach. First applications demonstrate that this Co-Creation-Wheel is multifunctional and international. It inspires, supports reflection of collaboration, stimulates interventions to enhance co-creation practices and human resource development (HRD) activities and is able to measure the quality of co-creation elements. Further research on its effects in co-creation practices is necessary, especially on the role of HRD in co-creation. Originality/value: This study is the first to design and validate a multifaceted, holistic conceptual and practical model of co-creation that is easy to use for innovators in practice and is multifunctional.