Cook Island may refer to:

• Cook Island of Kiritimati, Kiribati
• Cook Island (New South Wales), an island
  • Cook Island Aquatic Reserve, a marine protected area in New South Wales
  • Cook Island Nature Reserve, a protected area in New South Wales
• Cook Island, South Sandwich Islands, central island in Southern Thule
• "Cook Island" is the adjectival demonym for people and things from the Cook Islands

• Cook Islands, self-governing democracy in the Pacific in free association with New Zealand
• Cook (disambiguation)