The exchange of technical personnel between organizational actors in a supply network has become known as Guest Engineering (GE). Despite increasing popularity as an inter‐organisational arrangement (especially in the automotive sector) it has generated relatively little academic research and therefore this paper seeks to extend our understanding of GE by exploring how its scope is determined, what motivates the participants and how the relationships evolve. The paper draws on extant GE, supply networks and Resource‐Based View (RBV) literature to derive research propositions that are used to analyse empirical work carried out with four automotive suppliers and four automotive OEMs. A number of preliminary conclusions are drawn. At a micro‐project level, the criticality of the individual ‘playing the GE role’ is highlighted, as are related concerns that collaborative team structures often fail to address broader social/cultural characteristics. At a macro‐project level, the study argues that difficulties and mistrust will often characterise integrated and competitively successful GE relationships. Finally, at a strategic level, GE needs to be understood as a process of resource transfer and transformation, and therefore the management of interdependency and power asymmetry are core considerations in effective adoption. The paper concludes with recommendations for further critical and practical work.