Ahmadu Seku Tall (also Ahmadu Sekou, Ahmadu al-Madani al-Kabir) was a Toucouleur ruler (Laamdo Dioulbé) of the Toucouleur Empire (1864-1892) and (Faama) of Ségou (now Mali) from 1864-1884 . Ahmadu Seku's father, El Hadj Umar Tall, conquered Ségou (then the heart of the Bambara Empire) on March 10, 1861. Not long afterwards, he began his conquest of the Fula empire of Massina, leaving Ahmadu as the Almami of Ségou.
After Umar Tall's 1864 death, his nephew Tidiani Tall succeeded him as head of the Toucouleur Empire. Ahmadu Seku continued to act as Faama of the eastern regions from Segou, suppressing the rebellions of several neighboring cities but quarrelling increasingly with his brothers. The French colonial army invaded the empire in the 1880s and 1890s, taking Ségou in 1892 and forcing Ahmadu Seku to flee to Sokoto in present-day Nigeria.
| Preceded by El Hajj Umar Tall |
Faama of Ségou 1864 - 1884 |
Succeeded by Madani Ahmadu Tall |
| Preceded by Muntaga Tall |
Faama of Nioro 1884 - 1890 |
Succeeded by French West Africa |
| Preceded by Mounirou Tall |
Faama of Masina 1890 - 1892 |
Succeeded by French West Africa |