The 2021 WTA Slovenia Open (also known as the Zavarovalnica Sava Portorož for sponsorship purposes) was a WTA 250 tournament played on outdoor hard courts.

It was the 7th edition of the Slovenia Open, last held in 2010.

It was primarily organised due to the cancellation of the Asian tournaments during the 2021 season because of the ongoing COVID-19 pandemic.

[1] This was Paolini's maiden WTA Tour singles title.

The following players received wildcards into the singles main draw: The following players received entry from the qualifying draw: The following pairs received wildcards into the doubles main draw: