ADERRA may refer to:

• Automobile Dealer Economic Rights Restoration Act, US legislation introduced in the 111th United States Congress to restore the economic rights of car dealers
• Aderra inc., a music technology company based in Los Angeles and London

• The signed letter of Muhammad al-Mahdi
• The signed letter of Muhammad al-Mahdi (Tawqee)
• The Signet
• The Signet, a magazine for members of Phi Sigma Kappa fraternity
• The Signet (magazine)
• The Sign of Diolyx (The Tomorrow People)
• The Sign Of Four
• The Sign of Four
• The Sign of the Cactus
• The Sign of the Cross (film)
• The Sign of the Malay
• The Sign of the Spade
• The Sign of Zorro
• The Signpost
• The Signpost (E. Arnot Robertson novel)
• The Signpost (newsletter)
• The Signpost (novel)
• The Signpost (Robertson novel)
• The Signpost (Wikipedia)
• The signs of Muhammad al-Mahdi's reappearance in Islamic traditions
• The Signs of the Zodiac
• The Sign (VHS, Region 1) (1994)
• The Sihra Brothers
• The Silbón
• The Silence (2006 film)