The WTO Ministerial Conference of 1999 was the third Ministerial-level meeting of the World Trade Organization, convened at the Washington State Convention and Trade Center in Seattle, Washington, USA, over the course of four days, from Tuesday, 30 November 1999 to Friday, 3 December 1999. Anti-globalization activists organized large-scale protests of the meeting, sometimes known as the Battle of Seattle. Direct action tactics forced the WTO Ministerial Conference to begin late on 30 November and contributed to the meeting ending without agreement on 3 December.

The World Trade Organization (WTO) is an intergovernmental organization headquartered in Geneva, Switzerland that regulates and facilitates international trade. Governments use the organization to establish, revise, and enforce the rules that govern international trade in cooperation with the United Nations System. The WTO is the world's largest international economic organization, with 164 member states representing over 98% of global trade and global GDP.