diff --git a/.clang-format b/.clang-format
index 196a8e48b32cb1bbb32ef0e48b24c20642270f51..5aceae71b52f20e6f3f157403bfbb934edba4cef 100644
--- a/.clang-format
+++ b/.clang-format
@@ -94,3 +94,16 @@ SpacesInSquareBrackets: false
 Standard:        Cpp11
 TabWidth:        3
 UseTab:          Never
+
+# Order alphabetically and by generality the included header files.
+IncludeCategories:
+  - Regex:           '^"[^/]+\"'
+    Priority:        10
+  - Regex:           '^"cling/'
+    Priority:        20
+  - Regex:           '^"clang/'
+    Priority:        30
+  - Regex:           '^"llvm/'
+    Priority:        40
+  - Regex:           '^<'
+    Priority:        50