Abu Abdallah Muhammad al-Zaghal (the Valiant) (Arabic: أبو عبد الله محمد الثالث عشر) (c. 1444 – c. 1494) was the 23rd Nasrid ruler of Granada in Spain. Christians called him Mahoma XIII el Zagal.

Muhammad fought in the Granada War next to his brother Abu'l-Hasan Ali, also known as "Muley Hacén".

He succeeded his brother in 1485. He abdicated in 1486. After passing the throne to his nephew Muhammad XII, also known as Boabdil, el Zagal ruled over a fractured remnant of the kingdom in its last days.

When Muhammad XII surrendered the Alhambra Palace to the Catholic Monarchs, el Zagal left for North Africa to gather an army. There he was imprisoned by the ruler of the Wattasid dynasty, Boabdil's friend, who ordered to blind him.

He presumably died in north-western Algeria, in Tlemcen, in 1494.

• Harvey, Leonard Patrick (1992), Islamic Spain 1250 to 1500, University of Chicago Press
• Irving, Washington (1832), Tales of the Alhambra, Éditions Phébus, 1998 (online edition)

• Nasrid dynasty, Granada (1237-1492)
• Nasrid dynasty of Granada (in Arabic) بنو نصر/النصريون/بنو الأحمر في غرناطة
• Requiem for Granada, TV film.