The International Day for Biological Diversity (or World Biodiversity Day) is a United Nations–sanctioned international holiday for the promotion of biodiversity issues. It is currently held on May 22.

From its creation by the Second Committee of the UN General Assembly in 1993 until 2000, it was held on December 29 to celebrate the day the Convention on Biological Diversity went into effect. In December 2000, the date was shifted to commemorate the adoption of the Convention on May 22, 1992 at the Rio Earth Summit, and partly to avoid the many other holidays that occur in late December.