The 1988 Frankfurt Cup, was a men's tennis tournament played on indoor carpet courts and in Frankfurt, West Germany that was part of the 1988 Grand Prix circuit.

It was the second edition of the tournament was held from 17 October until 23 October 1988.

First-seeded Tim Mayotte won the singles title.

[3][4] Tim Mayotte defeated Leonardo Lavalle, 4–6, 6–4, 6–3 Rüdiger Haas / Goran Ivanišević defeated Jeremy Bates / Tom Nijssen, 1–6, 7–5, 6–3