This research draws on Asanuma’s concept of relation-specific skills in order to analyse collaboration between automaker and supplier. The cultivation of relation-specific skills has been conventionally regarded as a key factor of competitiveness in the Japanese automotive industry. Yet, the concept has been described mostly in economic terms only. This research attempts to extend this view by analysing the role of informal institutions (trust) in developing relation-specific skills. By drawing on expert interview data within the frame of a case study research approach, we gathered data from a leading multinational automotive supplier in its facilities in Japan and Germany. The results show that the influence of trust plays a role in determining relation-specific skills. In conclusion, we hypothezise that cultural homophily positively influences the cultivation of relation-specific skills.