Sofia Costoulas (Greek: Κωστούλα, romanized: Kostoula; born 2 April 2005) is a Belgian tennis player.

[1] Costoulas has a career-high singles ranking by the Women's Tennis Association (WTA) of 248 and a best doubles ranking of 229.

On the ITF Junior Circuit, she had a career-high combined ranking of No.

She lost the girls' singles final of the 2022 Australian Open to Petra Marčinko.

[2] She had already reached the Wimbledon junior doubles final in 2021.