<p>As International Organizations (IOs) have proliferated and expanded their mandates, they have become embedded in increasingly dense and interconnected regime complexes. These evolving governance structures pose new external challenges for IO secretariats, which must navigate relationships with both member states and other IOs within their sector. Yet, comparative evidence on how IO staff perceive these external influences remains scarce. This article addresses this gap in two steps. First, it introduces perceived autonomy as a new empirical variable, drawing on an original multi-IO survey. Second, it examines IO staff perceptions of interactions with other IOs. The results reveal that IO staff perceive moderate autonomy, with variations across four key global governance sectors—trade, finance, security, and climate change—as well as within them. Notably, IO staff do not view interactions with other IOs as particularly problematic, challenging common assumptions in the regime complexity literature about governance congestion. By reintroducing the perspective of IO staff into comparative global governance research, this article offers new insights into how governance complexity is experienced from within.</p>