Thiago Seyboth Wild

Thiago Seyboth Wild (Brazilian Portuguese: [tʃiˈaɡu ˈzajbutʃi ˈviwdʒi];^{[clarification needed]} born 10 March 2000) is a Brazilian professional tennis player. He has a career-high ATP singles ranking of world No. 58, achieved on 20 May 2024 and a doubles ranking of No. 197, achieved on 22 May 2023. He is currently the No. 4 singles player from Brazil.

Seyboth Wild played on junior circuit and had a combined ITF ranking of No. 8, attained in January 2018. He won the boys' singles title at 2018 US Open.

In March 2020, at just 19 years old, Seyboth Wild won his first ATP Tour title at 2020 Chile Open, defeating second seed Casper Ruud in the final. Then he became the youngest Brazilian ATP titlist until João Fonseca's trophy at 2025 Argentina Open.

Seyboth Wild was born on 10 March 2000 in the municipality of Marechal Cândido Rondon of Paraná in the Southern Region of Brazil. His father, Claudio Ricardo Wild, manages several tennis academies in Brazil, and his mother, Gisela Christine Seyboth, is a dentist. Had he not continued to pursue a career in tennis, he said that he would like to follow in his mother's footsteps as a doctor; he studied biomedicine and administration prior and hopes to continue pursuing his degree in the future. Seyboth Wild has a sister, Luana. Seyboth Wild is of paternal Romanian and Russian descent, whereas his mother is of German heritage.

Through his mother, Seyboth Wild is the great-great-grandson of Dietrich Klagges, an early member of the Nazi Party. Brazilian newspaper O Globo reported in 2023 that Seyboth Wild had boasted to his former girlfriend through WhatsApp about his family's connection to Adolf Hitler, writing, "My [great-]great-grandfather ... was Hitler’s predecessor .... He was the one who brought him over from Austria and taught Hitler the life."

After beginning to play tennis at the age of 4 with the assistance of his father, Seyboth Wild moved to Rio de Janeiro at the age of 14 to begin a career professionally. "I feel happy on the court. It's the place I'm supposed to be. The court gives me limits, but at the same time it gives me the space and inspiration to do what I like. Tennis allows me to be myself and express myself on court." Seyboth Wild commented on the sport.

Wild became the second Brazilian to win a junior Grand Slam, at the 2018 US Open, on 9 September, joining Tiago Fernandes. He also made the junior semifinal at the Roland Garros, and at the doubles of US Open and French Open.

Seyboth Wild made his ATP main draw debut at the 2018 Brasil Open after receiving a wildcard into the singles main draw.