The 1989 Estoril Open was a women's tennis tournament played on outdoor clay courts at the Estoril Court Central in Oeiras, Portugal that was part of the Category 2 tier of the 1989 WTA Tour. It was the first edition of the tournament and was held from 17 July through 23 July 1989. Third-seeded Isabel Cueto won the singles title.

Isabel Cueto defeated Sandra Cecchini 7–6^(7–3), 6–2

• It was Cueto's 1st title of the year and the 4th of her career.

Iva Budařová / Regina Rajchrtová defeated Gaby Castro / Conchita Martínez 6–2, 6–4

• It was Budařová's only title of the year and the 4th of her career. It was Rajchrtová's only title of the year and the 1st of her career.

• ITF tournament edition details Archived 2016-06-06 at the Wayback Machine
• Tournament draws