diff --git a/vtk-compat_gl.changes b/vtk-compat_gl.changes
index 3786913..a030baf 100644
--- a/vtk-compat_gl.changes
+++ b/vtk-compat_gl.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Thu Oct 26 08:48:16 UTC 2017 - dimstar@opensuse.org
+
+- Add conflict between the -devel-doc variants.
+
 -------------------------------------------------------------------
 Tue Oct 24 11:55:17 UTC 2017 - dimstar@opensuse.org
 
diff --git a/vtk-compat_gl.spec b/vtk-compat_gl.spec
index 8865b3a..77787a0 100644
--- a/vtk-compat_gl.spec
+++ b/vtk-compat_gl.spec
@@ -183,6 +183,10 @@ use VTK to do 3D visualisation.
 %package devel-doc
 Summary:        VTK API documentation
 Group:          Documentation/HTML
+%if %compat_gl
+# vtk and vtk-compat_gl have the same set of documentation.
+Conflicts:      vtk-devel-doc
+%endif
 
 %description devel-doc
 VTK is a software system for image processing, 3D graphics, volume
diff --git a/vtk.changes b/vtk.changes
index 3786913..a030baf 100644
--- a/vtk.changes
+++ b/vtk.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Thu Oct 26 08:48:16 UTC 2017 - dimstar@opensuse.org
+
+- Add conflict between the -devel-doc variants.
+
 -------------------------------------------------------------------
 Tue Oct 24 11:55:17 UTC 2017 - dimstar@opensuse.org
 
diff --git a/vtk.spec b/vtk.spec
index c5c7bbe..ff4a537 100644
--- a/vtk.spec
+++ b/vtk.spec
@@ -183,6 +183,10 @@ use VTK to do 3D visualisation.
 %package devel-doc
 Summary:        VTK API documentation
 Group:          Documentation/HTML
+%if %compat_gl
+# vtk and vtk-compat_gl have the same set of documentation.
+Conflicts:      vtk-devel-doc
+%endif
 
 %description devel-doc
 VTK is a software system for image processing, 3D graphics, volume