2021 I.ČLTK Prague Open

The 2021 I.ČLTK Prague Open was a professional tennis tournament played on outdoor clay courts. It was the 28th and 16th editions of the tournament which was part of the 2021 ATP Challenger Tour and the 2021 ITF Women's World Tennis Tour. It took place in Prague, Czech Republic from 3 to 9 May 2021.

Men's singles main-draw entrants

The following players received wildcards into the singles main draw:

The following player received entry into the singles main draw as a special exempt:

The following players received entry from the qualifying draw:

The following players received wildcards into the singles main draw:

The following player received entry using a protected ranking:

The following players received entry from the qualifying draw:

Tallon Griekspoor def. Oscar Otte 5–7, 6–4, 6–4.

Jule Niemeier def. Dalma Gálfi, 6–4, 6–2

Marc Polmans / Sergiy Stakhovsky def. Ivan Sabanov / Matej Sabanov 6–3, 6–4.

Anna Bondár / Kimberley Zimmermann def. Xenia Knoll / Elena-Gabriela Ruse, 7–6, 6–2