Design Thinking is a human-centred methodology for innovation, which has evolved from the study of the unique ways in which designers 'think', and 'practice' (Bauer & Eagen, 2008). While there is emerging research into the learning and teaching of Design Thinking, it is often anecdotal, i.e. reflection rather than research-based, and there is general lack of rigorous evaluation of curricula. This paper presents a PhD research project that explores how Design Thinking expertise can be best introduced, developed, and nurtured within Product Design and Business higher education programmes. The project involves the development, evaluation and refinement of a Design Thinking curriculum, including the design of learning outcomes, content, learning activities, assessment, and resources. The evaluation focuses on the students' learning experience, and their development of Design Thinking expertise. Participants also contribute to the further development of the curriculum. The research uses Action Research, Design and Co-Design methodologies, with embedded Case Studies, and draws upon both qualitative and quantitative methods. A number of key theories and constructs inform the curriculum design, in particular Design Thinking (Brown, 2008), Constructivism (Cross, 2011), Experiential Learning (Kolb, 1984), and Bloom's Learning Domains (Bloom, 1965).