Sea Shepherd Conservation Society

The Sea Shepherd Conservation Society (SSCS) is a non-profit, marine conservation activism organization based in Friday Harbor on San Juan Island, Washington, in the United States. Sea Shepherd employs direct action tactics to achieve its goals, most famously by deploying its fleet of ships to track, report on and actively impede the work of fishing vessels believed to be engaged in illegal and unregulated activities causing the unsustainable exploitation of marine life.

Sea Shepherd has been criticised by some environmental groups and national governments that oppose its tactics. The Japanese government, whose whaling industry is a leading target of the organization's efforts, has called Sea Shepherd eco-terrorists for "impeding their research".