diff --git a/style/c/.clang-format b/style/c/.clang-format
index 6da79a0..0683c55 100644
--- a/style/c/.clang-format
+++ b/style/c/.clang-format
@@ -67,6 +67,7 @@
     Priority: 1
 IncludeIsMainRegex: '(Test)?$'
 IndentCaseLabels: false
+IndentExternBlock: NoIndent
 #IndentPPDirectives: None # Unknown to clang-format-5.0
 IndentWidth: 8
 IndentWrappedFunctionNames: false
diff --git a/style/cpp/.clang-format b/style/cpp/.clang-format
index d92a3f1..4922cf6 100644
--- a/style/cpp/.clang-format
+++ b/style/cpp/.clang-format
@@ -78,6 +78,7 @@
   - Regex:           '.*'
     Priority:        6
 IndentCaseLabels: true
+IndentExternBlock: NoIndent
 IndentRequiresClause: true
 IndentWidth:     4
 IndentWrappedFunctionNames: true