Just to add more detail on the issue, I tried on a fresh sid install (with Docker) and the following works well:
root@62ae0c72d468:/# python3 get-pip.py Collecting pip Downloading pip-8.1.1-py2.py3-none-any.whl (1.2MB) 100% |################################| 1.2MB 118kB/s Collecting setuptools Downloading setuptools-20.9.0-py2.py3-none-any.whl (508kB) 100% |################################| 512kB 98kB/s Collecting wheel Downloading wheel-0.29.0-py2.py3-none-any.whl (66kB) 100% |################################| 71kB 105kB/s Installing collected packages: pip, setuptools, wheel Successfully installed pip-8.1.1 setuptools-20.9.0 wheel-0.29.0 root@62ae0c72d468:/# pip3 install virtualenv Collecting virtualenv Downloading virtualenv-15.0.1-py2.py3-none-any.whl (1.8MB) 100% |################################| 1.8MB 85kB/s Installing collected packages: virtualenv Successfully installed virtualenv-15.0.1 root@62ae0c72d468:/# virtualenv test Using base prefix '/usr' New python executable in /test/bin/python3 Also creating executable in /test/bin/python Installing setuptools, pip, wheel...done. root@62ae0c72d468:/# source test/bin/activate (test) root@62ae0c72d468:/# python Python 3.5.1+ (default, Apr 17 2016, 16:14:06) [GCC 5.3.1 20160409] on linux Type "help", "copyright", "credits" or "license" for more information. >>> the resulting "test" virtual environment is created correctly. So it would seem a problem of the Debian package and not of upstream virtualenv or pip. Thanks a lot for maintaining this package, steko -- Stefano Costa @stekosteko Editor, Journal of Open Archaeology Data