diff --git a/COPYING b/COPYING
index 310fd52c27..80fac091d3 100644
--- a/COPYING
+++ b/COPYING
@@ -47,6 +47,9 @@ various drivers, support functions and header files within Xen-aware
 Linux source trees. In all such cases, license terms are stated at the
 top of the file or in a COPYING file in the same directory.
 
+Sphinx documentation is licensed under CC-BY 4.0.  See
+docs/README.source for more specific information.
+
 In some cases, compatible 3rd party code has been imported into the
 Xen tree, retaining the original license, such as
   - AES-128 3.0
diff --git a/docs/README.source b/docs/README.source
new file mode 100644
index 0000000000..f20fa92c28
--- /dev/null
+++ b/docs/README.source
@@ -0,0 +1,32 @@
+Sphinx documentation:
+
+All source rendered by Sphinx is licensed under CC-BY-4.0.
+
+You are free to:
+  Share:
+    Copy and redistribute the material in any medium or format.
+  Adapt:
+    Remix, transform, and build upon the material for any purpose, even
+    commercially.
+
+Under the following terms:
+  Attribution:
+    You must give appropriate credit, provide a link to the license, and
+    indicate if changes were made. You may do so in any reasonable manner, but
+    not in any way that suggests the licensor endorses you or your use.
+  No additional restrictions:
+    You may not apply legal terms or technological measures that legally
+    restrict others from doing anything the license permits.
+
+See https://creativecommons.org/licenses/by/4.0/ for full details.
+
+This includes:
+  * All ReStructured Text files:          docs/*/*.rst
+  * The Sphinx configuration file:        docs/conf.py
+  * Content in Sphinx-exclusive subdirs:  docs/*-guide/*
+
+
+Other documentation:
+
+There are a variety of text documents in various formats.  These, given no
+explicit license guidance, fall under Xen's default GPL-2.0 license.
diff --git a/docs/admin-guide/index.rst b/docs/admin-guide/index.rst
index f725d75ebe..ad1f508a79 100644
--- a/docs/admin-guide/index.rst
+++ b/docs/admin-guide/index.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 Admin Guide
 ===========
 
diff --git a/docs/admin-guide/microcode-loading.rst b/docs/admin-guide/microcode-loading.rst
index 1858ed4627..8265b917a9 100644
--- a/docs/admin-guide/microcode-loading.rst
+++ b/docs/admin-guide/microcode-loading.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 Microcode Loading
 =================
 
diff --git a/docs/conf.py b/docs/conf.py
index 73b7b9bfa2..50e41501db 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+# SPDX-License-Identifier: CC-BY-4.0
 #
 # Configuration file for the Sphinx documentation builder.
 #
diff --git a/docs/guest-guide/index.rst b/docs/guest-guide/index.rst
index 108e0b8d77..03c5b37bd1 100644
--- a/docs/guest-guide/index.rst
+++ b/docs/guest-guide/index.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 Guest documentation
 ===================
 
diff --git a/docs/guest-guide/x86/hypercall-abi.rst b/docs/guest-guide/x86/hypercall-abi.rst
index dee25853d4..edb10b1b2e 100644
--- a/docs/guest-guide/x86/hypercall-abi.rst
+++ b/docs/guest-guide/x86/hypercall-abi.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 Hypercall ABI
 =============
 
diff --git a/docs/guest-guide/x86/index.rst b/docs/guest-guide/x86/index.rst
index a368392087..121cddca62 100644
--- a/docs/guest-guide/x86/index.rst
+++ b/docs/guest-guide/x86/index.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 x86
 ===
 
diff --git a/docs/hypervisor-guide/code-coverage.rst b/docs/hypervisor-guide/code-coverage.rst
index 6c7552d691..641aac25fc 100644
--- a/docs/hypervisor-guide/code-coverage.rst
+++ b/docs/hypervisor-guide/code-coverage.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 Code Coverage
 =============
 
diff --git a/docs/hypervisor-guide/index.rst b/docs/hypervisor-guide/index.rst
index cbcae398a2..7ba37b6e54 100644
--- a/docs/hypervisor-guide/index.rst
+++ b/docs/hypervisor-guide/index.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 Hypervisor documentation
 ========================
 
diff --git a/docs/index.rst b/docs/index.rst
index 31bb8927f2..7bd9955a97 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
 The Xen Hypervisor documentation
 ================================
 
