The 2021 Portugal Ladies Open was a professional women's tennis tournament played on outdoor hard courts.

It was the second edition of the tournament which was part of the 2021 ITF Women's World Tennis Tour.

It took place in Caldas da Rainha, Portugal between 13 and 19 September 2021.

[1] The following players received wildcards into the singles main draw: The following player received entry using a junior exempt: The following player received entry using a special exempt: The following players received entry from the qualifying draw: