In the LOGO educational programming language, the Turtle was your cursor. You were supposed to imagine a turtle with a pen in its stomach that would follow LOGO commands on your behalf, drawing pictures with its pen. Some implementations helpfully drew a picture of a turtle to help you imagine.

In Terry Pratchett's Discworld universe, the turtle is what holds the four elephants, which in turn hold the Discworld. The turtle is also the form of the god Om when it is... uh... small, in the book "Small Gods".