Around the year 160 AD the Romans founded a colony and two forts there; linguists reconstructed their Latin name as (Castra) Valentia on the base of the town's medieval name Wallenzin[3] first mentioned in 1181.

The history of the settlement after the fall of the Roman Empire is in darkness, until the year 1266 when Welzheim was granted city's-rights.

The district of Welzheim became part of the county of Waiblingen in 1938, and has been a deanery of the Evangelical-Lutheran Church in Württemberg since 1977.

During World War II there was a small concentration camp near the city, today identified euphemistically to as simply "The Prison."

The most famous prisoner during this time was the Communist labor unionist Friedrich Schlotterbeck, of the Luginsland resistance group.