In 122 AD, the later Wiesbaden is mentioned for the first time with its Roman name as "Aquae Mattiacorum", the "Waters of Mattiacae". In the late 4th century, the settlement is called "Mattiacae Aquae". The current name was first mentioned by the scholar and historian Einhard in his report from 830. In his Latin text, he refers to Wiesbaden, which he had visited in 828 and 829, as the "place that is called Wisibada in more recent times". In a roughly contemporaneous copy of the text, the name reads "Wisabada". Other forms of the name are "Wisibadun" (documented in 965), "Wisebadon" (documented in 1022, 1043) and "Wisibad" (documented in 1123).

From the 13th and 14th centuries, the current name gradually became established. After many attempts at interpretation, an explanation based very closely on the Latin form of the name has been considered plausible since the research of German scholar Adolf Bach. Bach and, following him, Otto Renkhoff assume that an old Germanic term lives on in the Latin word: "Mattiaker" is derived from "matha", "Mahdland", "land that can be harvested". The - unknown - Germanic place name continued to exist alongside the Latin one and replaced it after the Romans left.

In Frankish times, "matha" was then replaced by the Old High German "wisa", "meadow", or the collective form "wisi", "meadow land", which basically had the same meaning. Earlier interpretations interpreted "wisa" as an Indo-European term for "hot water" or "salt bath" or thought to recognize an Old High German "wisu", good, i.e. "healing", in the place name.