The 1998 Porsche Tennis Grand Prix was a women's tennis tournament played on indoor hard courts at the Filderstadt Tennis Club in Filderstadt in Germany that was part of Tier II of the 1998 WTA Tour.

It was the 21st edition of the tournament and was held from 5 October until 11 October 1998.

Unseeded Sandrine Testud won the singles title and earned $79,000 first-prize money.

[1] Sandrine Testud defeated Lindsay Davenport 7–5, 6–3 Lindsay Davenport / Natasha Zvereva defeated Anna Kournikova / Arantxa Sánchez-Vicario 6–4, 6–2