Adolfo Daniel Vallejo (born 28 April 2004) is a Paraguayan tennis player.
Vallejo has a career-high ATP singles ranking of world No. 287 achieved on 24 June 2024. He is currently the No. 1 Paraguayan tennis player.[2]
On the ITF Junior Circuit, Vallejo had a career-high junior ranking of No. 1, achieved in August 2022.[3]
In 2021, he won the Junior Orange Bowl in Plantation, Florida, defeating Bruno Kuzuhara in the final. He was the first Paraguayan player to win the tournament and only the second to reach the final after Víctor Pecci.
In March, he won his first Challenger title in São Léopoldo, Brazil, defeating Enzo Couacaud in the final. He became the youngest Paraguayan to win an ATP Challenger title and the fourth Paraguayan champion in ATP Challenger Tour history and first since Ramon Delgado in 2009.[4][5] As a result, he reached the top 300 on 6 May 2024.