diff --git a/doc/source/index.rst b/doc/source/index.rst
index f562850..fecf98a 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -80,6 +80,14 @@
 
    library
 
+Support Policy
+--------------
+
+.. toctree::
+   :maxdepth: 2
+
+   stable_branch_support_policy
+
 Indices and tables
 ==================
 
diff --git a/doc/source/stable_branch_support_policy.rst b/doc/source/stable_branch_support_policy.rst
new file mode 100644
index 0000000..87e3ad1
--- /dev/null
+++ b/doc/source/stable_branch_support_policy.rst
@@ -0,0 +1,30 @@
+Stable Branch Support Policy
+============================
+
+Since the `Extended Maintenance policy`_ for stable branches was adopted
+OpenStack projects will keep stable branches around after a "stable" or
+"maintained" period for a phase of indeterminate length called "Extended
+Maintenance". Prior to this resolution Tempest supported all stable branches
+which were supported upstream. This policy does not scale under the new model
+as Tempest would be responsible for gating proposed changes against an ever
+increasing number of branches. Therefore due to resource constraints, Tempest
+will only provide support for branches in the "Maintained" phase from the
+documented `Support Phases`_. When a branch moves from the *Maintained* to the
+*Extended Maintenance* phase, Tempest will tag the removal of support for that
+branch as it has in the past when a branch goes end of life.
+
+The expectation for *Extended Maintenance* phase branches is that they will continue
+running Tempest during that phase of support. Since the REST APIs are stable
+interfaces across release boundaries, branches in these phases should run
+Tempest from master as long as possible. But, because we won't be actively
+testing branches in these phases, it's possible that we'll introduce changes to
+Tempest on master which will break support on *Extended Maintenance* phase
+branches. When this happens the expectation for those branches is to either
+switch to running Tempest from a tag with support for the branch, or blacklist
+a newly introduced test (if that is the cause of the issue). Tempest will not
+be creating stable branches to support *Extended Maintenance* phase branches, as
+the burden is on the *Extended Maintenance* phase branche maintainers, not the Tempest
+project, to support that branch.
+
+.. _Extended Maintenance policy: https://governance.openstack.org/tc/resolutions/20180301-stable-branch-eol.html
+.. _Support Phases: https://docs.openstack.org/project-team-guide/stable-branches.html#maintenance-phases