Oja may refer to:
Oja (river), river in La Rioja, Spain Oja (surname), an Estonian and Finnish surname 5080 Oja, main-belt asteroid Ōja Station, railway station in Hashikami, Japan Oja's rule, a model of properties of neurons in the brain "Oja", a 2019 song by Reminisce Ọjà, musical instrument of the Igbo people
See also Öja (disambiguation) OJA (disambiguation) Oya (disambiguation) Ojha, an Indian surname