Rebellious collective action is rare, but it can occur when subordinates are severely discontented and other circumstances are favorable. The possibility of rebellion is a check sometimes the only check on authoritarian rule. Although mutinies in which crews seized control of their vessels were rare events, they occurred throughout the Age of Sail. To explain the occurrence of this form of high-risk collective action, this article holds that shipboard grievances were the principal cause of mutiny. However, not all grievances are equal in this respect. We distinguish between structural grievances that flow from incumbency in a subordinate social position and incidental grievances that incumbents have no expectation of suffering. Based on a case-control analysis of incidents of mutiny compared with controls drawn from a unique database of Royal Navy voyages from 1740 to 1820, in addition to a wealth of qualitative evidence, we find that mutiny was most likely to occur when structural grievances were combined with incidental ones. This finding has implications for understanding the causes of rebellion and the attainment of legitimate social order more generally.