The development approach embodied in design for assembly (DFA) has been demonstrated effectively in different industrial sectors and through the design of a multitude of products. However, little effort has been applied to improving development methods for the assembly operations and processes used to fabricate these products. If the benefits of concurrent engineering are to be fully realized, a more holistic approach to unifying a product’s design with development of its assembly processes is needed. This paper provides a description of our approach to establishing an environment for coordinated product and assembly process development. The steps in a product’s development cycle are introduced and the concepts of design for assembly and concurrent engineering defined. Using DFA methods as a motivation, an approach to assembly process development is derived. Referred to as Systematic Assembly Process Development (S-APD), assembly processes are defined and analyzed by using standardized generic assembly operations. To address problems created by using concurrent engineering in product/process development, two mechanisms are described. Since the focus of developing a product (i.e. how well does it perform and cost) differs from developing its assembly processes (i.e. making products at the necessary volumes), the concept of an interface reference context is introduced as a coordination mechanism and applied to development of unmanned composite low-cost aircraft. Moreover, in identifying which elements of the design are to be assembled with a specific set of production technologies, a synchronous thread is instantiated to link product and assembly process development efforts in a temporal context. Different approaches are reviewed to resolve potential conflicts related to concurrency effects generated during simultaneous product and assembly process development.