The Arroyo Urugua-í o Grande is a river in the province of Misiones, Argentina, part of the Cuenca del Plata. It originates in the Sierra de Misiones near the city of Bernardo de Irigoyen and flows approximately 100 kilometres before emptying into the Río Paraná, south of Puerto Bosetti and northwest of Puerto Libertad in the Iguazú department. The river's average discharge is 54 m³/s. Its watershed, one of the most extensive in the province, is bounded by the Sierras Morena, de Misiones, and de la Victoria, spanning parts of the Iguazú and General Belgrano departments.

A hydroelectric dam on the lower river creates a reservoir, and the upper and middle sections of the watershed are protected within the Parque Provincial Urugua-í. The river flows through the southern portion of this park in a southeast-to-northwest direction. Tributaries include the Sarita River, Arroyo de las Cabeceras, and the Uruzú River. The park was established in part to offset the flooding of approximately 8,800 hectares of the lower river basin caused by dam construction.

Park rangers have conducted organized descents of the river, with at least one documented traverse running from the Reserva de Vida Silvestre Urugua-í to the confluence with the Arroyo Falso, with wildlife observation as a primary objective. At the river's mouth, the Arroyo Urugua-í can also be reached by paddling the Río Paraná from the direction of Puerto Bemberg, a roughly two-hour recreational route that also offers views of the Paraguayan shoreline.