The 2021 Hamburg European Open was a combined men's and women's tennis tournament played on outdoor clay courts.

The tournament took place at the Am Rothenbaum in Hamburg, Germany between 6 and 18 July 2021.

The event was scheduled a week earlier than the usual late July date to avoid scheduling conflicts with the 2020 Summer Olympics.

[1][2] This was Ruse's maiden WTA Tour singles title.

*per team The following players received wildcards into the main draw: The following players received entry from the qualifying draw: The following players received entry as lucky losers: The following pairs received wildcards into the doubles main draw: The following pair received entry using protected ranking: The following pair received entry from the qualifying draw: The following pair received entry as lucky losers: The following players received wildcards into the main draw: The following players received entry from the qualifying draw: The following player received entry as a lucky loser: The following pair received a wildcard into the doubles main draw: