| Singles | |
|---|---|
| 1988 Belgian Open | |
| 1987 Champion |  Kathleen Horvath |
| Champion |  Arantxa Sánchez |
| Runner-up |  Raffaella Reggi |
| Final score | 6–0, 7–5 |
Kathleen Horvath was the defending champion but lost in the first round to Silvia La Fratta.
Arantxa Sánchez won in the final 6–0, 7–5 against Raffaella Reggi.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.
Zina Garrison (quarterfinals)
Katerina Maleeva (second round) Raffaella Reggi (final) Arantxa Sánchez (champion)
Isabel Cueto (semifinals)
Neige Dias (quarterfinals) Kathleen Horvath (first round)
Mercedes Paz (quarterfinals)World No. 2 and second-seeded Steffi Graf defeated Martina Navratilova in the final, 6–4, 4–6, 8–6, to win the women's singles tennis title at the 1987 French Open. Third-seeded Chris Evert was the defending champion, but she lost in the semifinals to world No. 1 Martina Navratilova.
The following is the result of the 1988 Virginia Slims of Oklahoma singles.
Chris Evert and Wendy Turnbull were the defending champions but did not compete that year.
Steffi Graf was the defending champion but did not compete that year.
Martina Navratilova and Gabriela Sabatini were the defending champions but did not compete that year.
Steffi Graf was the defending champion and won in the final 6–3, 6–2 against Helena Suková.
Bettina Bunge and Katerina Maleeva were the defending champions but only Maleeva competed that year with Raffaella Reggi.
Gabriela Sabatini was the defending champion of the singles event of the 1989 Virginia Slims of Florida tennis tournament but lost in the third round to Terry Phelps.
Steffi Graf was the defending champion but did not compete that year.
Martina Navratilova was the defending champion but lost in the semifinals to Natasha Zvereva.
Neige Dias was the defending champion but lost in the second round to Tine Scheuer-Larsen.
Gabriela Sabatini was the defending champion and won in the final 6–2, 5–7, 6–4 against Arantxa Sánchez.
Lori McNeil won in the final 6–1, 6–3 against Elna Reinach.
Nicole Provis and Elna Reinach won in the final 4–6, 6–4, 6–2 against Raffaella Reggi and Arantxa Sánchez Vicario.
Judith Wiesner won in the final 6–1, 6–2 against Sylvia Hanika.
Steffi Graf was the defending champion and won in the final 6–4, 6–2 against Katerina Maleeva.
Claudia Kohde-Kilsch and Jana Novotná were the defending champions but only Novotná competed that year with Tine Scheuer-Larsen.
First-seeded Martina Navratilova was the defending champion and won in the final 6–2, 6–3 against Chris Evert.
Martina Navratilova and Pam Shriver were the defending champions and won in the final 3–6, 6–3, 6–2 against Patty Fendick and Jill Hetherington.
Top-seeded Manuela Maleeva was the defending champion but fell in the quarterfinals to Kate Gompert. Fourth-seed Andrea Temesvári claimed the title and $38,000 first prize money by defeating Zina Garrison in the final.
