ISO/IEC 26550:2013 provides a reference model consisting of an abstract representation of the key processes of software and systems product line engineering and management, and the relationships between the processes. In the product line there are two development lifecycles (domain engineering and application engineering), the involvement of variabilities, and two process groups (organizational management and technical management). Domain Engineering lifecycle processes define and implement domain assets commonly used by member products within a product line, while Application Engineering lifecycle processes develop applications by exploiting the domain assets including common and variable assets. During domain engineering, product line variability, which reflects the specific needs of different markets and market segments, are explicitly defined. Variabilities are embedded in domain assets and during application engineering they are selected based on the defined variability models. Organizational Management process group helps organizations to establish and improve capabilities for nurturing their product lines from conception to retirement and for establishing and managing relationships with customers, providers, and other key stakeholders. Meanwhile, Technical Management process group provides actual means used to support, monitor, and control the activities of both domain engineering and application engineering of a product line. The reference model for software and systems product line engineering and management of ISO/IEC 26550:2013 can be used in subsequent standardization efforts to create appropriate standards for requirements engineering and management, design, realization, verification and validation, and organizational and technical management processes, tools, and methods of software and systems product line engineering.