This thesis concerns specifically the discipline of product design, and the main question is how can designers be supported in understanding the culture of their intended users. The reason for this study is that designers are experiencing difficulties and uncertainties with regard to their intended users, as these users live in cultures with which the designers are not familiar. By means of an extensive series of empirical projects, this thesis explores the concept of culture in the context of design. It proposes a framework (based on socio-cultural dimensions) and a tool (a set of cards) that help designers to become aware of possible cultural barriers with respect to participatory design research as well as to design. In addition, the study describes the opportunities (including five intentions) for a culture-conscious approach to design.