Amadu Seku (Var.: Ahmadu Shaykhu ibn Ahmadu, Ahmadu II) (Ruled 19 March 1845 - 27 February 1853) was a ruler (Imam or Amir al-Mu´minin) of the nineteenth-century Massina Empire in what is now Mali.
Amadu Seku's father, Seku Amadu, founded the Fula Massina Empire as an independent Muslim state in 1820. Seku Amadu died in 1845 after a number of conquests, leaving his son control of the Macina region, Djenné, and Tomboctou. However, Amadu Seku abdicated the throne in favor of his own son, Amadu Amadu in 1852. The Massina Empire fell to El Hadj Umar Tall's Toucouleur Empire in 1862, leading to Amadu Amadu's capture and execution; another of Amadu Seku's sons, Balobo, led a rebellion against Umar Tall that led to the Toucouleur's death, but not the freedom of the Massina people.