Government agreements (GAs) are key drivers of future policies in most countries with multi-party coalitions and also serve to limit policy initiatives not included in the GA. However, little is known about how this 'grip' of GAs over policies changes over time. Throughout the legislative term, new policy issues arise and public demands change. If governments are responsive, they address these issues, leading to increasing divergence from the GA: policy drift. The central question this study addresses is whether the changing social and politico-strategic environment leads to a fading grip of the GA on policy, causing policy drift vis-à-vis the initial policy program. Using an agenda-setting approach, we map the policy priorities of the GAs to two measures of policy priorities of Belgian governments from 1992 to 2006: ministerial council decisions and state of the union speeches. Despite evidence of intrusion of policy issues from beyond the GA, we do not find policy drift, in terms of systematic temporally determined deviation from the 'original' policy priorities. Hence, this study finds that GAs, at least in Belgium, maintain control over the policy agenda, both as a source and a constraint, on future policies throughout the legislature.