Summary In this report we try to get a deeper insight into what we can theoretically expect, what we already know from research, and what we can also measure empirically, about the effects of employee participation at the organisational level in Belgium. We focus on representative participation, i.e. participation via trade union-based participation structures. This report is based on an overview of recent research findings, as well as testing expectations from this research literature for Belgium based on recently collected survey data. The review of the literature shows that for various outcomes there are conflicting conclusions, that the existing research is remarkably scarce for Belgium, but also that there are a number of confirmed and expected effects that we can test for the Belgian context. When we empirically test this on the basis of the survey data, we learn from a large scale HIVA - KU Leuven employee survey (N = 3.527, 2019) that the presence of trade union representatives has a positive effect on the chances of training, the knowledge of employee rights and benefits, and the effective exercise of collective labour rights. Workers in organisations with trade union representation also indicate that they feel more confident that the quality of their job will not deteriorate. However, these associations are not reflected in the management survey data collected for Belgium as part of the European Company Survey (ECS fourth wave, 2019). After checking for company size and sector, there is no association between, on the one hand, the presence of participation structures such as the Works Council or Health and Safety Comitee and, on the other hand, certain company management and management practices (e.g. job security, (digital) innovation, working in a team, autonomy, training, employee motivation, and relationship between employees and employers). Both employee representatives and management indicate in surveys that the influence of employee representation on management decisions is rather limited. The ...