Hamburg European Open

The Hamburg European Open or German Open Hamburg is a tennis tournament held annually on the clay courts of the Am Rothenbaum in Hamburg, Germany. The first edition was held in 1892 and was reserved for men, the first women's edition was held in 1896.

The women's tournament, which would take the name WTA Hamburg, was discontinued in 2002 and restored in 2021. From 2000 to 2008 the men's tournament it was part of the Masters Series circuit and since 2009 it has been part of today's ATP Tour 500 category.

In 1981, the prize pool for the men's tournament was raised to $200,000 for the first time. In 1990, at the same time as the birth of the ATP Tour, the Hamburg tournament was included in the circuit of the best world tournaments after those of the Grand Slam, called the ATP Championships Series Single Week, which would later take on other names including the Masters 1000. Hamburg was inserted in the calendar immediately after the Internationals of Italy.

The matches in the tournament were played in best of five sets until 2007. In 2009 its place as the third Masters on clay was taken by the Madrid Open, the Hamburg tournament was relegated to the ATP 500 category and relocated to the third week of July.

In 2019 the tournament was renamed the Hamburg European Open. The 2020 edition, initially canceled due to the COVID-19 pandemic, was held in September.