Tiago Carvalho Santos (born 23 July 2002) is a Portuguese professional footballer who plays as a right-back for Ligue 1 club Lille.
Santos is mostly a youth product of Sporting CP, with stints at the academies of Oeiras, Sacavenense, and moving to the U23 side of Estoril in 2021.
On 9 July 2022, he was promoted to Estoril's senior side for the 2022–23 season.
Santos made his professional and Primeira Liga debut as a starter in a 2–2 tie with Rio Ave on 19 August 2022, which he as assisted on the first goal of the match.
He received the Young Player of the Month award in Primeira Liga for April 2023.
Santos finished the 2022–23 season with 7 assists in 30 league appearances for Estoril.
During the summer 2023 transfer window, Santos attracted interest from Benfica, who had an offer in the region of €5 million accepted by Estoril for the right-back.
However, Sporting CP invoked an "anti-rival" clause inserted into Santos' contract when he joined Estoril, which stated that the Lions were owed €20 million if the player was sold to Benfica or Porto; for that reason, the move collapsed.
On 5 July 2023, Santos signed a five-year contract with Ligue 1 club Lille, who paid €6.5 million for the right-back.
He made his debut for Les Dogues on 11 August, starting in a 1–1 draw away at Nice in the 2023–24 Ligue 1's opening match.
Thirteen days later, Santos made his debut in European competitions, starting in a 2–1 home victory over HNK Rijeka in the play-off round of the UEFA Europa Conference League.
On 26 November 2023, Santos scored his first professional goal, from outside the penalty box, in a 2–0 league victory away at Olympique Lyonnais.
Santos made his international debut for the Portugal U21s on 8 September 2023, starting in a 3–0 home victory over Andorra in a qualifying match for the 2025 UEFA European Under-21 Championship.
