Uncertainty, as a key source of macroeconomic fluctuations, has gained heightened attention, especially after the 2007 financial crisis. Understanding cross‑country uncertainty spillovers is therefore essential for interpreting economic and political developments. Using the frequency connectedness approach within the Quantile Vector Autoregression (QVAR) framework and monthly data from 2008 to 2025, this study examines uncertainty spillovers among 16 OPEC+ members and 16 European countries, one of the main oil and gas‑importing blocks. The findings show that: (1) total connectedness in both groups is generally above 70 percent and varies across horizons; (2) in OPEC+, Qatar and Mexico are the main transmitters of uncertainty, while Angola and Azerbaijan are the key receivers, whereas in Europe Austria and the United Kingdom act as transmitters and the Netherlands and Spain as receivers; (3) countries’ net roles differ across short‑ and long‑term horizons; (4) the dominance of long‑term connectedness in Europe indicates that uncertainty is primarily transmitted through fundamental macroeconomic channels rather than temporary shocks; and (5) Iran, as a major node in the OPEC+ network, is most influenced by Oman and Mexico, while exerting its strongest effects on Oman, Azerbaijan, and Saudi Arabia. The primary contribution of this study is the dynamic mapping of the uncertainty network between OPEC+ and European economies within a quantile-frequency framework, which provides a tool for evaluating economic resilience by disentangling short- and long-term time horizons. These results provide a clearer understanding of uncertainty transmission mechanisms and countries’ interdependent roles for policymakers.