Sebastian Leth Frandsen (born 24 May 1994) is a Danish handball player who plays for Fredericia HK.

[1] He joined Ribe-Esbjerg HH on a two-year contract, starting at the begin of the 2014–15 season after being without a club due to Vejle Håndbold bankruptcy.

While playing for Ribe-Esbjerg he debuted for the Danish national team on November 6th 2015 against Spain.

[2] Bjerringbro-Silkeborg announced on 26 September 2015 that Sebastian Frandsen would be joining the club at the start of the 2016/2017 season.

[3] TTH Holstebro announced on 18 October 2017 that Sebastian Frandsen would be joining the club at the start of the 2018/2019 season.