The Sea Shepherd Conservation Society (SSCS) is a non-profit, marine conservation organization based in Friday Harbor on San Juan Island, Washington, in the United States.

In the United States Sea Shepherd has a 501(c) tax exempt status. Most of the organization's revenue—83.2 percent—is spent on its programs, while 16.7 percent of revenue is spent on administrative and fundraising. It is supported by private and corporate donations, lectures by Watson, internet advertising, and grants. The group is operated by volunteers and a small number of paid staff.

Sea Shepherd engages in conventional protests and direct actions to protect marine wildlife. Sea Shepherd operations have included interdiction against commercial fishing, shark poaching and finning, seal hunting, and whaling. The group has been active in intervening against fishing and poaching in the South Pacific, the Mediterranean, and in waters around the Galapagos Islands. In addition to their direct action campaigns, Sea Shepherd works on ocean issues such as plastic pollution. Sea Shepherd chapters across the world organize onshore cleanups throughout the year to pick up debris near oceans, streams, and rivers.