Joachim II may refer to:

• Joachim II Hector, Elector of Brandenburg (1505–1571)
• Patriarch Joachim II of Constantinople (R. from 1860 to 1863 and from 1873 to 1878)

• Environmental Centre ARCTUROS
• Environmental change
• Environmental Change Network
• Environmental Charter High School
• Environmental chemist
• Environmental Chemistry (journal)
• Environmental Choice Program
• Environmental Commissioner of Ontario
• Environmental commissioner of ontario
• Environmental communication
• Environmental concern
• Environmental conservation
• Environmental consultancy
• Environmental contaminant
• Environmental contamination
• Environmental contract
• Environmental Control
• Environmental Control and Life Support System
• Environmental control system (aircraft)
• Environmental crime
• Environmental Crime Prevention Program
• Environmental crimes
• Environmental Criminology
• Environmental criminology
• Environmental Data and Information Service