ABSTRACT Interactions between the EU and IGOs ˗ such as joint statements, verbal public disagreements, formal cooperation agreements, and IGO dispute resolution involving the EU ˗ have increased in the past decades. We address the question What determines the EU’s interactions with formal IGOs? by carrying out a big data-based sentiment analysis of all news published online between 1999 and 2017. Using over 30,000 events machine-coded by the Global Data Event Language and Tone (GDELT) database, we construct an annual measure for the dyadic relations between the EU and 36 formal IGOs. We find that when the EU has observer or member status in an IGO, this significantly and positively affects the quantity of interactions, while increasing the level of conflict in these interactions. Policy overlap between the EU and the IGO also increases the level of conflict in their interactions. Surprisingly, IGO authority is not relevant for these interactions.