The Turtle System

The Turtle System is a free educational program developed at the University of Oxford, designed to support the new Computer Science component of the National Curriculum. It is based on Turtle Graphics, an idea invented by Seymour Papert, in which an imaginary turtle moves around the computer screen drawing as it goes, all under the control of instructions given by a computer program. This sort of programming, and the results it produces, are easy to understand because they are so immediately visual. But the Turtle System provided here shows that Papert‘s idea can go well beyond simple graphics, to provide a basis for fascinating and powerful programs that introduce fundamental concepts of software engineering and artificial intelligence.


The Turtle System requires no installation — simply click one of the buttons below to download the single executable file, and then double-click that file to run. The first time you run the program, Windows may warn you that it is of unknown origin, and therefore potentially unsafe. Click ‘Run Anyway’ to indicate that you trust the source, and this message will not bother you a second time. (On Windows 8, you need to click ‘More Information’ before the option to ‘Run Anyway’ appears.)

Download the Turtle System v11
Windows Only

Click on the button above to download version 11 of the Turtle System, a well-tested version including Turtle BASIC, Turtle Pascal, and Turtle Python. Security information (SHA1 checksum).

Download the Turtle System v12
Windows Only

Click on the button above to download version 12 of the Turtle System (beta). Note that this version is still under development. Already however it has several additional features, most notably support for multi-dimensional arrays. Security information (SHA1 checksum).

Further Information

Please see the Documentation page for detailed information about the Turtle System and how to use it. For a discussion of the principles behind the System, see the About page, or Peter Millican’s articles in the Autumn 2014 and Spring 2015 editions of Computing at School’s SwitchedOn magazine (reproduced below). For any additional information, or to make any suggestions for future developments, please contact us — details on the Contact page.


This project is funded by the Department for Education, with matched funding from various sources within the University of Oxford (the Department of Computer Science, the Van Houten Fund, and a private donor at Hertford College). It is housed in the University of Oxford’s Faculty of Philosophy.