The Saint Petersburg Declaration may refer to:
- Saint Petersburg Declaration of 1868, a treaty prohibiting the use of less deadly explosives that might merely injure and thus create prolonged suffering of combatants
- Saint Petersburg Declaration on Forest Law Enforcement and Governance in Europe and North Asia (2005) - see Illegal logging
It may also refer to:
- St. Petersburg Declaration (St. Petersburg, Florida, 2007), a manifesto calling for reform within Islam - see Secular Islam Summit