"Cotton Tail" is a 1940 composition by Duke Ellington. It is based on the rhythm changes from George Gershwin's "I Got Rhythm". The first Ellington recording (2 May 1940) is notable for the driving tenor saxophone solo by Ben Webster. Originally an instrumental, "Cotton Tail" later had lyrics written for it by Ellington. Later, more lyrics were written, based on the 1940 recording, by Jon Hendricks, and recorded by Lambert, Hendricks and Ross.

Cottontail may refer to:

• Cottontail rabbit
  • Dice's cottontail, Sylvilagus dicei
  • Omilteme cottontail, Sylvilagus insonus
  • Desert cottontail, Sylvilagus audubonii
  • Manzano mountain cottontail, Sylvilagus cognatus
  • Mexican cottontail, Sylvilagus cunicularis
  • Eastern cottontail, Sylvilagus floridanus
  • Mountain cottontail, Sylvilagus nuttallii
  • Appalachian cottontail or rarely Allegheny cottontail, Sylvilagus obscurus
  • New England cottontail, Sylvilagus transitionalis