606 may refer to:

• 606, the year
• The drug "606" or "compound 606", which became known as arsphenamine
• Roland TR-606 Drum Machine
• 606 (radio show), the BBC Radio 5 Live phone-in and accompanying internet discussion forum
• Bloomingdale Trail, or "the 606," an urban elevated trail in Chicago, converted from the Bloomingdale Line
• Area code 606, in Kentucky
• 606 Group (band), a progressive rock band from Stockport, England
• Monark 606, a sailboat class.

• A-606 (disambiguation)