1998 Estoril Open – Men's singles

Àlex Corretja was the defending champion, but did not participate this year.

Alberto Berasategui won the tournament, beating Thomas Muster in the final, 3–6, 6–1, 6–3.

Seeds
• # 🇪🇸 Félix Mantilla (quarterfinals)

• # 🇪🇸 Carlos Moyá (semifinals)

• # 🇪🇸 Alberto Berasategui (champion)

• # 🇪🇸 Albert Costa (quarterfinals)

• # 🇫🇷 Fabrice Santoro (first round)

• # 🇦🇹 Thomas Muster (final)

• # 🇪🇸 Francisco Clavet (first round)

• # 🇪🇸 Albert Portas (first round)