A1C may refer to:

• Airman First Class, the third enlisted rank in the United States Air Force
• Glycated hemoglobin (hemoglobin A1c or Hb_A1c), a surrogate marker for blood glucose levels

• IGunCon
• I Gusti Bagus Oka
• I Gusti Ngurah Rai International Airport
• I Gusti Putu Okamona
• I Gusti Putu Oka Mona
• Iguta
• Igutsaat Fjord
• IG VII
• I. G. Voznesenskii
• Igwali Island
• Igwe Felix Onochie
• Igwe of Nnewi kingdom
• Igwe Okafo
• I. G. Wosnesenski
• IGWT
• IGWT (disambiguation)
• IG XII
• IGYCRCTL
• Igy jottem
• Igzim
• I går såg jag ditt barn, min Fröja
• I.H. 35E
• IHAB
• Ihab Al-Msmare
• Ihab Al-Youssef