- The Helsinki Rules on the Uses of the Waters of International Rivers is an international guideline regulating how rivers and their connected groundwaters that cross national boundaries may be used
- It was adopted by the International Law Association (ILA) in Helsinki, Finland in August 1966
- It led to the creation of the United Nations’ Convention on the Law of Non-Navigational Uses of International Watercourses
- It is applicable to all drainage basins that cross national boundaries, except where other agreement between bordering nations exists
- In spite of its adoption by the ILA, there is no mechanism in place that enforces the rules
- In 2004, it was superseded by the Berlin Rules on Water Resources