No module named packaging

First update your pip version itself. You can take a look at this answer

pip3 install --upgrade pip

And then try to install packaging, if its not already installed by now.

pip3 install packaging

If I understand well, the issue that causes confusion in other's replies is that you have an error while running pip itself, which prevents self-updates of pip or installation of the missing package.

As requested, please state exactly how you installed Python 3 and pip. Ubuntu 14 does not come with Python 3.5.

For diagnosis, please give the output of

which python3

that is probably /usr/bin/python3 and refers to the system-wide python3 while your pip is located in /usr/local/bin/pip3.

Suggested solution: Uninstall system pip with apt-get remove python3-pip and try again with either pip3 or python3.5 -m pip.

I recently had the same error. Unfortunately none of the other answers solved my problem. Finally installing the following package resolved my issue:

sudo apt install python3-packaging

For older versions of Python you may need to adjust the command:

sudo apt install python-packaging