Oikos is ancient Greek for "household". It may also refer to:

• Oikos (journal), a journal on ecology
• Oikos International, a sustainability-oriented student association
• Oikos, Cyprus, a village in Cyprus
• Oikos University, a Christian school in Oakland, California
• Oikos (Swedish think-tank), a conservative Swedish think-tank, founded 2020
• Oikos, an alternate name for Kontakion, a Byzantine hymn
• Ōiko [ja], a Japanese legendary strong woman in the Heian period
• Oikos/Oykos, a North American brand of Danone yogurt

• Oecus
• Oeconomus
• Oikophobia
• Ecology