Decentralized identity management systems (DIMS) open up new opportunities for identity management, meaning that decentralization and the lack of a central party are expected to provide users’ of DIMS with more control and transparency over their personal information. Thereby, DIMS are in contrast to traditionally used centralized identity management systems (CIMS) that are, nowadays, often realized by the implementation of so-called SSO schemes, which allow users to authenticate once with a particular service provider and to use these credential for every subsequent authentication. In the literature, control over personal information is often hypothesized to affect information self-disclosure; however, only little is known on how control affects disclosure behaviour depending on the design of IMS user interfaces. We show through a multi-group structural equation analysis that perceived control is a stronger predictor on user disclosure behaviour in the DIMS environment compared to the CIMS. Furthermore, the results of our study provide practical implications on user interface design based on the effect that perceived ease of use of interface does not necessarily enhance user attitudes towards the IMS.