The International Weed Science Society (IWSS) was formed in 1975, by individuals from Europe, North America, South America, and the Asian-Pacific area, to deal with global weed science issues. The Society has held six highly successful International Weed Control Congresses, in Australia (1992), Denmark (1996), Brazil (2000), South Africa (2004), Canada (2008) and China (2012).
The IWSS is a worldwide scientific organization, open to all who are interested in weeds and their control. The formation of IWSS was promoted actively by the six existing regional weed science societies. The purpose of IWSS is to supplement and complement their vital role. Additionally, IWSS provides benefits and functions of a weed science society not currently existing at a national or regional level.