Waltendorf (German: [ˈvaltn̩ˌdɔɐ̯f]) is a district of the Austrian city of Graz.

It had a population of 12.158 (January 2023) and covers an area of 4.48 square kilometres.

Within the north of the district, next to the Ragnitz brook, there is one of the largest collection of high-risers in Graz, called 'Berliner Ring'.

Some of the high risers have the solar water heating systems on their roof tops.

Collectively this solar water system is one of the largest in the city of Graz.