A. niger may refer to:

• Acromyrmex niger, an ant species found in southern Brazil and Paraguay
• Agelastes niger, the black guineafowl, a bird species found in humid forests of Central Africa
• Allocyttus niger, the black oreo, a fish species found around Australia and New Zealand
• Andricus niger, a gall wasp species in the genus Andricus
• Aspergillus niger, the black mold, a fungus species

See also

• Niger (disambiguation)