See main article: article and 2021 Zagreb Ladies Open.
Silvia Njirić and Dejana Radanović were the defending champions[1] but chose not to participate.
Barbara Haas and Katarzyna Kawa won the title, defeating Andreea Prisăcariu and Nika Radišić in the final, 7–6(7–1), 5–7, [10–6].