Bayer can refer to:

• Bayer AG, the German chemical and pharmaceutical company
• Bayer filter, a color filter mosaic also known as a Bayer pattern, used in digital camera image sensors
• Bayer designation for star names
• KFC Uerdingen 05, formally known as FC Bayer 05 Uerdingen, a German football club
• Bayer Leverkusen, a German sports and football club
• Johann Bayer, a German astronomer, who introduced star designation named after him (see Bayer designation)

Bayer | Bayer