Diaby is a surname, and may refer to:

• Cheikh Moustapha Diaby Alias Diaby Koweït (1951-2008), President of the African institutions presidium.

President du conseil supérieur islamique de Côte d’Ivoire [Islamic Affairs-Awqaf]. A former counsel for both presidents - Félix Houphouet Boigny et Henri Konan Bédié. He was also a leading candidate for president of the Ivory Coast in election which were to be scheduled later in 2009. He was also a great humanitarian and family man. He was known for his generosity.

• Abdoulay Diaby (born 1991), Malian football player

• Abou Diaby (born 1986), French football midfielder

• Aboubakar Diaby Ouattara, Ivorian diplomat

• Alassane Diaby (born 1995), French-born Malian football player

• Karamba Diaby (born 1961), Senegalese-born German chemist and politician

• Kariata Diaby (born 1995), Ivorian basketball player

• Karim Coulibaly Diaby (born 1989), French-Ivorian football striker

• Lassina Diaby (born 1992), Ivorian footballer

• Mohamed Diaby (born 1990), Ivorian football midfielder

• Moussa Diaby (born 1999), French football forward

• Oumar Diaby (born 1990), French football forward

• Sékana Diaby (born 1968), former Ivorian football defender

• Souleymane Diaby (born 1987), Ivorian football striker of Guinean descent

• YaYa Diaby (born 1999), American football player