Bayan may refer to:

• Bayan-Aul, Pavlodar, Kazakhstan
• Bayan, Dashkasan, Azerbaijan
• Bayan, Oghuz, Azerbaijan
• Bayan County, in Harbin city, Heilongjiang Province, China
• Bayan or Piyan, an old name for Khorramshahr, Iran
• Bayan, Fars, a village in Fars Province, Iran
• Bayan, Hamadan, a village in Hamadan Province, Iran
• Bayan area an area within the Hawalli governorate of Kuwait

• Bayan, Sistan and Baluchestan, a village in Sistan and Baluchestan Province, Iran

In Bábism, a Bayán , or exposition, denotes the whole body of the works of the Báb, the central one being the Persian Bayán. Some modern Bábís (followers of the Báb) call themselves 'Bayaní' after this title of the Báb's writings. Bahá'ís also see this work as holy, since they consider their founder to be the fulfillment of the Báb's main prophetic anticipation.

The Bagong Alyansang Makabayan (Filipino: lit. New Patriotic Alliance) or Bayan is an alliance of militant organizations. It was founded on International Workers' Day, May 1, 1985 as part of the opposition during the Marcos dictatorship.