This article examines the Cyprus Emergency (1955–1959) to test the force structure thesis. According to the thesis, armies that deploy more manpower per armored vehicle would succeed in counterinsurgency because they could win people’s trust, secure intelligence from civilians, and use force selectively. Using the congruence method of within-case analysis, I show that the causal process and logic of the force structure argument are not confirmed in the favorable case of Cyprus. Despite its preference for infantry and police units, the British garrison failed to win over the people and persuade civilians to share information about the insurgent; besides, Britain’s intelligence breakthroughs and selective violence did not result from the logic of the force structure thesis, nor did the conflict end as the argument would predict. Political conditions, instead, played a greater role. Ultimately, the case of Cyprus warns against the reassuring belief, inherent in the force structure thesis, that military organizational adjustments in favor of manpower can pave the way to victory against irregular opponents.