Coalitions of states are often portrayed as effective in war. This study examines whether thehigher success of coalitions on the battlefield is due to the fact that they tend to fight againststructurally weaker opponents, rather than an inherent advantage from coalition warfare itself.Using the Belligerents in Battle 1900–2003 dataset, a quantitative analysis of 20th-century battlesis conducted. A logistic regression analysis tests whether coalition membership influences theprobability of victory when controlling factors such as initiative, home turf and force ratio amongcoalition members. The results indicate that while coalitions win battles more often than singlestates, this success can be explained partly by coalitions’ favorable starting conditions e.g.,numerical superiority and initiative. Once these factors are accounted for, the direct effect of beinga coalition on winning outcomes disappears. The study concludes that coalitions’ success largelyresults from facing weaker opponents, and not necessarily from the coalition dynamics per se.