diff --git a/dev-docs/source/Python3.rst b/dev-docs/source/Python3.rst
index 85915a6d2ad75e2d9e1a1055742578ff3d79f80b..248ef49e1e69ff5c4b87e102df0115606d63c6dd 100644
--- a/dev-docs/source/Python3.rst
+++ b/dev-docs/source/Python3.rst
@@ -12,13 +12,28 @@ migration strategy for Mantid.
 Building Against Python 3
 #########################
 
-This is currently only possible on a Linux system with a pre-installed version of python 3 and you will need to have
-the latest version of the `mantid-developer` package installed. Once installed run cmake as standard but with the additional option ``-DPYTHON_EXECUTABLE=/usr/bin/python3``. Please note that
-reconfiguring an existing Python 2 build is not supported - a build in a fresh build directory is required.
+This is currently possible on Ubuntu or Windows.
+Please note that reconfiguring an existing Python 2 build is not supported - a build in a fresh build directory is required.
+
+Ubuntu
+^^^^^^
+
+Install the latest version of the `mantid-developer` package. Once installed run cmake as standard but with the additional option ``-DPYTHON_EXECUTABLE=/usr/bin/python3``.
 
 .. warning::
    Do not install python packages via ``pip``. Install packages only from the system repositories.
 
+Windows
+^^^^^^^
+
+All of the required packages are in the third-party bundle that will be fetched for you.
+
+To build from the command line run cmake as standard but with the additional option ``-DWITH_PYTHON3=ON``.
+
+To build from the GUI ensure the previous cache has been deleted, set the source and build directories as usual
+but before clicking configure click "Add Entry" and add an entry with the name ``WITH_PYTHON3`` of type ``BOOL``
+and ensure the Value is checked. Now proceed to configure and generate as usual.
+
 Supporting Python 2 and 3
 #########################
 
diff --git a/dev-docs/source/index.rst b/dev-docs/source/index.rst
index 8c43f6fb93a35abb7ab04da79d05039f1a43131c..1bd00d7980ca5ab63883dee9915a444f07e9565c 100644
--- a/dev-docs/source/index.rst
+++ b/dev-docs/source/index.rst
@@ -47,7 +47,7 @@ Guides
    Configure a doxygen build locally.
 
 :doc:`Python3`
-   Building with Python 3 (Linux only).
+   Building with Python 3 (Ubuntu/Windows).
 
 `C++ Introduction <https://www.mantidproject.org/New_Starter_C%2B%2B_introduction>`_
    Exercises for learning C++.
@@ -207,7 +207,7 @@ GUI Development
 
 :doc:`ISISReflectometryInterface`
    An example of a complex C++ interface that uses MVP.
-   
+
 =========
 Workbench
 =========