Original equipment manufacturers (OEMs) typically outsource the industrialization of components to suppliers. Hence, the OEMs are dependent on the suppliers’ capabilities to perform industrialization projects. However, suppliers often experience various difficulties when involved in the OEMs’ product development projects. Therefore, the aim of the paper is to explore challenges that suppliers face during industrialization projects, their causes and the effects. Actions to mitigate these challenges are further explored. Based on an in-depth single case study at a Swedish supplier from the metal components industry, the study resulted in seven challenging issues during industrialization projects from a supplier perspective.