Gelson Dany Batalha Martins (Portuguese pronunciation: [ˈʒɛlsɐ̃ mɐɾˈtĩʃ]; born 11 May 1995) is a professional footballer who plays as a winger for Super League Greece club Olympiacos.

[7] Martins made his professional debut on 24 August 2014, coming on as a late substitute for Lewis Enoh in a 1–0 away win against S.C. Olhanense in the Segunda Liga.

[13] On 11 June 2018, Martins requested that his contract with Sporting be terminated[14] following an incident in May in which a group of around 50 supporters invaded the club's training centre and assaulted several players and staff members.

[19] Martins made his La Liga debut on 20 August 2018 in a 1–1 away draw with Valencia CF, where he played 18 minutes in place of Antoine Griezmann.

[24] He made his first Ligue 1 appearance on 2 February, providing an assist for Aleksandr Golovin early in the first half and also being involved in Cesc Fàbregas' goal in the 2–1 home victory over Toulouse FC.

[26] The following 1 February, at the 30-minute mark of an away fixture against Nîmes Olympique, he repeatedly pushed referee Mikael Lesage in retaliation for his teammate Tiémoué Bakayoko's ejection seconds before, and was too sent off as his team eventually lost 3–1.

[35] He also represented the nation at the 2015 FIFA U-20 World Cup, scoring in the group stage against Senegal[36] and in the round of 16 against hosts New Zealand[37] in an eventual quarter-final exit.

[41] He made his debut in the competition on 20 June, playing roughly 30 minutes in the 1–0 group stage defeat of Morocco after replacing Bernardo Silva.