Uskelanjoki is a river of Finland. It flows into the Archipelago Sea through the town of Salo. The course of the river follows a large, NE–SW oriented bedrock fracture line which begins from the river estuary in Halikonlahti bay and goes up through the lower reaches of the river and its tributary Terttilänjoki in north. Other tributaries of Uskelanjoki are Rekijoki and Hitolanjoki in north, Kurajoki in Pertteli and Vähäjoki near Salo.