A. aeneus may refer to:

• Abacetus aeneus, a ground beetle found in Egypt and Cyprus
• Aneides aeneus, the green salamander, found in the United States
• Anolis aeneus, the bronze anole, a lizard found in the Caribbean and South America
• Antiguraleus aeneus, an Australian sea snail
• Ariodes aeneus, a synonym of Netuma thalassina, the giant catfish
• Aspergillus aeneus, a fungus
• Astyanax aeneus, the banded tetra, a fish found in Central and South America
• Autocrates aeneus, an Asian beetle