Rúben Afonso Borges Semedo (born 4 April 1994) is a Portuguese professional footballer who plays as a central defender for Qatar Stars League club Al-Khor.

[5] Semedo spent the 2013–14 season with the B team in the Segunda Liga, his first appearance in the competition occurring on 25 August 2013 as he played the full 90 minutes in a 1–0 home win against Trofense.

He made his competitive debut – winning his first trophy in the process – on 9 August, coming on as a late substitute in a 1–0 victory over Benfica in the Supertaça Cândido de Oliveira.

[16] After Javier Calleja took over as head coach on 25 September he fell out of favour, and having seen himself become a rotation player his stint was also plagued by injuries, which ultimately required surgery in December.

[18] The decision to sign him attracted some criticism, but sporting director Emilio Vega stated that the player would be in good shape once the season began because he played some matches while in prison.

[23] He scored his first goal for the team on 30 July, with a close-range effort following a corner from Georgios Masouras after Aleš Hruška saved Yassine Meriah's shot, in a 4–0 home win over Viktoria Plzeň in the UEFA Champions League's second qualifying round.

[32] Semedo joined Al-Duhail of the Qatar Stars League on 1 August 2022, on a three-year contract with an annual salary of €5 million; Olympiacos retained 50% of the player's rights.

[38] On 24 March 2016, Semedo marked his debut for the Portugal under-21 team with a goal, scoring the opener in a 4–0 home defeat of Liechtenstein in the 2017 UEFA European Under-21 Championship qualifiers played in Ponta Delgada.

[39] In October 2019, while still awaiting trial for alleged crimes in Spain, he received his first call-up for the senior team ahead of UEFA Euro 2020 qualification matches against Luxembourg and Ukraine.

[41] In January 2018, it was announced that Semedo would stand trial for an altercation in a bar in Valencia the previous November, when the player allegedly brandished a pistol and made threats while he was nursing an injury.