Modularity-in-design (MID) and modularity-in-production (MIP) relationship has been gaining the attention of scholars and practitioners along the years. However, the literature does not specify how this connection occurs and its implications. This paper analyzes the relationship between MID and MIP within the automotive scenario and investigates its main technical and organizational implications. Through an abductive, matched-pair case study carried out in two large automakers, the study gathered data from interviews, on-site observations, and eld notes from all interactions within the plants. The paper indicates that (i) both automakers prioritize modular design before modular production, characterizing a productrelated approach, and (ii) the investigated automotive companies have different approaches when developing MID. One automaker focuses on product functionalities to develop the modules; the other company dedicates efforts towards a MID-MIP relationship through the industrial condominium concept. Results indicate signi cant propositions to be tested regarding MID-MIP connection, with original insights from two make-to-order (MTO) automotive companies. modular product architecture. Changes in the hierarchies in production systems and inter-rm systems create tensions with product architecture, encouraging its rede nition [2]. Therefore, other studies have been defending that the changes towards separability, recombinability, exibility, loose coupling, process independence and autonomy, would affect decisions regarding component commonality, combinability, standardized interfaces and function interactions.Nevertheless, there are occasions when MID-MIP relationships may have a two-way trajectory (e.g., [1, 6,[31][32][33]). Such MID-MIP relationship trajectory and its respective organizational effects depend on the unit of analysis considered [32], suggesting that there are contingencies that moderate MID-MIP connection. MID-MIP paths result from [31]: (i) previous and current con guration of the examined organization; (ii) product architecture characteristics; (iii) rate of technological change and organizational learning.Modularity can be improved when its concept extends to manufacturing processes [9]. In fact, there is currently more consensus indicating that higher degree of MID over time enables manufacturing structure changes towards a higher MIP level, i.e., product architecture can generate technical and organizational changes in production processes, which characterizes a product-related approach. Furthermore, some authors claim that modularity choices in product development processes affect further decisions and activities regarding manufacturing processes, enabling MIP (e.g., [2,7,29,34]). However, it is noteworthy that companies may have different goals when applying modularity, which may lead to distinct levels of relationships between MID and MIP and different strategies and objectives [2,10]. Table 1 summarizes the theoretical evidence regarding the MID-MIP interrelationship, while Fig. 1 indica...