The Rio Ruidoso is a 30-mile (48 km) long river located in the Sierra Blanca and Sacramento Mountains in Lincoln County and Otero County, New Mexico in the United States and is part of the Rio Ruidoso Watershed.

The Spanish term, río ruidoso, translated into English means literally "noisy river".

The headwaters of the Rio Ruidoso are located near the top of 11,981-foot (3,652 m) Sierra Blanca Peak, in the rugged Sierra Blanca mountains, which is located within the Mescalero Apache Indian Reservation.

They merge in Cow Canyon approximately 1-mile (1.6 km) west of the point at which the south fork merges with the north fork.

Several fish species live within the waters of the Rio Ruidoso, including: