They mention the possibility of a pre-Latin term Těttare, potentially connected to the Indo-European root teter- (commonly used for various types of gallinaceous birds).

The first appearance of the hydronym in Christian written sources dates back to 1189; however, its first mention in Arabic chronicles could have occurred around the 10th century with a transliterated form such as Tāt.r.

The Tiétar River begins at a place called La Venta del Cojo, in the municipality of Rozas de Puerto Real, where various springs, gorges, and streams feed its course until it reaches the Monfragüe National Park.

The river empties into the Tagus in the Monfragüe National Park after nearly 150 km, near Villarreal de San Carlos.

Its hydrological regime is pluvio-nival, with a maximum flow in winter (rain) and spring (snowmelt), and a marked minimum in summer.