Civil-military relations are characterized by a fundamental dilemma. To lower coup risk, leaders frequently empower the military, which satisfies the armed forces with the status quo and enables them to fight against threats challenging the civilian leadership. Simultaneously, a too powerful military itself constitutes a potential threat that is capable of overthrowing the government. Our research adds to this debate by examining the impact of mechanization, that is, the degree to which militaries rely on armored vehicles relative to manpower, on coup risk. We discuss several (opposing) mechanisms before developing the theoretical expectation that higher levels of mechanization should lower the likelihood of a coup due to the increased costs of coup execution. Empirical evidence strongly supports this claim and, thus, contributes to our understanding of the emergence of coups as an essential breakdown of civil-military relations, while adding to the debate surrounding the many trade-offs leaders face when coup-proofing their regimes.