On a daily basis we (in) directly make use of functions of various infrastructures: we drive on roads and bridges or we live without worries behind the safety of a dike. Only when there are cracks in the dike or a particular bridge is not accessible due to for example a broken pillar, we realize how critical these infrastructures are for our society and economy. These infrastructures are not build to last forever and they are susceptible to breakdowns, especially as some are reaching the end of their technical lifespan. Building new infrastructures is simply not an option, as this is often financially and logistically not feasible. Getting as much as possible out of the remaining technical lifespan of such critical infrastructures is then down to employing innovative maintenance strategies, such as risk and opportunity based asset management, as is being done in the ROBAMCI project, initiated by Deltares. Management and maintenance of infrastructures already takes place in a multi-actor environment. Adding systematic approaches on top of this multi-actor environment requires maintenance managers to further integrate their decision making processes. However, analysis have shown that there is a clear lack of this integrated decision making. Literature has further shown that this could be as a result of a lack of information sharing between organizations. Improving inter-organizational information sharing, however first requires further understandings. This research project is done with the goal to achieve that understanding. A case-study in the context of ROBAMCI was used to study this concpt in a practical environment. The asset in this case was a sea-lock complex located in Delfzijl, which not only performs functions for shipping, but also has various other direct and indirect functions, influencing for example local nature, economy and regional water management. Theoretical knowledge, gained from literature studies, was then used to interpret the data from in-depth interviews with employees of identified organizations. The empirical findings, interpreted through various sources of literature showed that there is a wide array of factors influencing inter-organizational information sharing in the case-study. Among the most mentioned and expected were trust, competing interests/self-interests and legislations & policies. Organizations also add value to the importance of personal physical interactions and even though the information sharing takes place between actors of one national government, concern for information misuse is also seen as a potential barrier for information sharing. The data has also led to the formation of some factor-relations, we see e.g. that trust forms a positive causal relation with not only information sharing itself, but also has a negative causal relation with concerns of the quality of the information. Data also makes it clear that there is an interrelation between the 3 levels of information sharing. These findings, backed by theory have led to the identification of 2 general fundamentals that can be taken into account when trying to further understand information sharing. The first one focuses on trust and legislations, whereas the second one addresses on the embeddedness of the information sharing levels. Conclusively it can be said that inter-organizational information sharing helps to make more efficient and effective decisions for the management and maintenance of assets. There are many factors that can either positively or negatively influence information sharing. It is recommended that through further studying factor relations their importance can be determined. This can also help to reduce the high number of factors and frameworks. For ROBAMCI it is recommended to use the results of this research as input for a maturity analysis focusing on the inter-organizational information management of organizations in the sector.