E123

E123 may refer to:
 * Amaranth (dye) or E123, a food additive
 * Element 123, a predicted chemical element; see Extended periodic table § Superactinides 
 * European route E123, a road in central Asia
 * E.123, an ITU-T recommendation
 * E-123 Omega, a recurring character in Sonic the Hedgehog games