Al-Adil I (in full al-Malik al-Adil Sayf al-Din Abu-Bakr ibn Ayyub, 1145–1218) is an Ayyubid-Egyptian general and ruler of Kurdish descent.

From his honorific "Sayf al-Din" (Sword of Faith) he is sometimes known to the Frankish crusaders as "Saphadin".

A gifted and effective administrator and organizer, Al-Adil provides crucial military and civilian support for Saladin's great campaigns (an early example of the great minister of war).

He is also a capable general and strategist in his own right, and the foundation and persistence of the Ayyubid state is as much his achievement as it is Saladin's.