In the engineer-to-order (ETO) business, companies provide customer value by customizing the products according to the customers' needs in a project-like manner. As a result, the number of individual product designs tends to proliferate, causing challenges in company operations, and product portfolio and product lifecycle management. In addition, if the company's product offering is not well productized, using the ETO model may further lead to poor understanding of the offering, deficient reuse of previous designs, and challenges in sales and making offers. A qualitative multiple case study was conducted to analyze the productization challenges of four ETO companies. On the basis of the challenges and the previous literature, a generic model for commercial and technical productization in ETO business was constructed and further tested in the companies. The model utilizes the logic of commercial and technical product structures. The product structure logic is linked to four different scales of product development processes to address different types of customer requests based on the complexity of the modification that the request necessitates. The model may support clarifying the product offerings of ETO companies to improve their design reuse, sales, and making offers. Further, the ETO order-related decision-making can be linked to product portfolio management targets and company strategy.