E126 or E-126 may refer to:

• Unbihexium, a hypothetical chemical element with atomic number 126
• Ponceau 6R, a red dye sometimes used as a food colorant with E number E126
• Enercon E-126, a wind turbine

• Treaty Establishing the European Community
• Treaty for the Limitation and Reduction of Naval Armaments
• Treaty for the Preservation and Protection of Fur Seals
• Treaty house
• Treaty Indian
• Treaty negotiation
• Treaty No. 6
• Treaty Number 1
• Treaty number four
• Treaty number four (Canada)
• Treaty Nº 7 Signing Site
• Treaty Oak (disambiguation)
• Treaty Oak (New York, New York)
• Treaty of 1082
• Treaty of 1819
• Treaty of 2004
• Treaty of Aachen (1502)
• Treaty of Accession (2005)
• Treaty of Accession (disambiguation)
• Treaty of Adrianople (1568)
• Treaty of Ahmet Pasha
• Treaty of Aimens
• Treaty of Aixe-Chapelle
• Treaty of Aixe-la-Chapelle
• Treaty of Aixe-la-Chapelle (1748)