diff --git a/docs/ClangFormatStyleOptions.rst b/docs/ClangFormatStyleOptions.rst
index e80cfd545b072131be0ad733d1f1f3acb92a7f33..031daeeaa123908e1f252f44f70e37eccf6befd0 100644
--- a/docs/ClangFormatStyleOptions.rst
+++ b/docs/ClangFormatStyleOptions.rst
@@ -275,6 +275,9 @@ the configuration (without a prefix: ``Auto``).
   * ``BS_Linux`` (in configuration: ``Linux``)
     Like ``Attach``, but break before braces on function, namespace and
     class definitions.
+  * ``BS_Mozilla`` (in configuration: ``Mozilla``)
+    Like ``Attach``, but break before braces on enum, function, and record
+    definitions.
   * ``BS_Stroustrup`` (in configuration: ``Stroustrup``)
     Like ``Attach``, but break before function definitions, and 'else'.
   * ``BS_Allman`` (in configuration: ``Allman``)
diff --git a/include/clang/Format/Format.h b/include/clang/Format/Format.h
index b234403bebc5aa15a77fad16f47153372c752f45..f8c8c373e143c04d6236cdd044f9dcebefef29f1 100644
--- a/include/clang/Format/Format.h
+++ b/include/clang/Format/Format.h
@@ -166,6 +166,9 @@ struct FormatStyle {
     /// Like \c Attach, but break before braces on function, namespace and
     /// class definitions.
     BS_Linux,
+    /// Like ``Attach``, but break before braces on enum, function, and record
+    /// definitions.
+    BS_Mozilla,
     /// Like \c Attach, but break before function definitions, and 'else'.
     BS_Stroustrup,
     /// Always break before braces.
diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 1e7996e31ae6909e60af8fa2f0b28f1e5fd8b207..382ae819ebfdc8327767b687a58f296e92840142 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -94,6 +94,7 @@ template <> struct ScalarEnumerationTraits<FormatStyle::BraceBreakingStyle> {
   static void enumeration(IO &IO, FormatStyle::BraceBreakingStyle &Value) {
     IO.enumCase(Value, "Attach", FormatStyle::BS_Attach);
     IO.enumCase(Value, "Linux", FormatStyle::BS_Linux);
+    IO.enumCase(Value, "Mozilla", FormatStyle::BS_Mozilla);
     IO.enumCase(Value, "Stroustrup", FormatStyle::BS_Stroustrup);
     IO.enumCase(Value, "Allman", FormatStyle::BS_Allman);
     IO.enumCase(Value, "GNU", FormatStyle::BS_GNU);
@@ -483,6 +484,7 @@ FormatStyle getMozillaStyle() {
   MozillaStyle.AlwaysBreakAfterDefinitionReturnType =
       FormatStyle::DRTBS_TopLevel;
   MozillaStyle.AlwaysBreakTemplateDeclarations = true;
+  MozillaStyle.BreakBeforeBraces = FormatStyle::BS_Mozilla;
   MozillaStyle.BreakConstructorInitializersBeforeComma = true;
   MozillaStyle.ConstructorInitializerIndentWidth = 2;
   MozillaStyle.ContinuationIndentWidth = 2;
diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index 4734ff350d72ceb9a10efe43963e5c6530715702..1e0c979d91df3739bd1995721154ad502f6ce111 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -2108,7 +2108,9 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
     return Right.HasUnescapedNewline;
   if (isAllmanBrace(Left) || isAllmanBrace(Right))
     return Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
-           Style.BreakBeforeBraces == FormatStyle::BS_GNU;
+           Style.BreakBeforeBraces == FormatStyle::BS_GNU ||
+           (Style.BreakBeforeBraces == FormatStyle::BS_Mozilla &&
+            Line.startsWith(tok::kw_enum));
   if (Style.Language == FormatStyle::LK_Proto && Left.isNot(tok::l_brace) &&
       Right.is(TT_SelectorName))
     return true;
diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index 345e109be8f715ff5eaa48e2b101b2515375df8a..97fd98ecb9479d151130feddf62a2c4233f8f9b4 100644
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -457,6 +457,8 @@ static bool ShouldBreakBeforeBrace(const FormatStyle &Style,
   switch (Style.BreakBeforeBraces) {
   case FormatStyle::BS_Linux:
     return InitialToken.isOneOf(tok::kw_namespace, tok::kw_class);
+  case FormatStyle::BS_Mozilla:
+    return InitialToken.isOneOf(tok::kw_class, tok::kw_struct, tok::kw_union);
   case FormatStyle::BS_Allman:
   case FormatStyle::BS_GNU:
     return true;
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index c9f63cef6649d6082251660e5f4b66d4910e1ff9..6aa7681ac59c3681bb6c152e647bcaf4037df192 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -8579,6 +8579,50 @@ TEST_F(FormatTest, LinuxBraceBreaking) {
                LinuxBraceStyle);
 }
 
+TEST_F(FormatTest, MozillaBraceBreaking) {
+  FormatStyle MozillaBraceStyle = getLLVMStyle();
+  MozillaBraceStyle.BreakBeforeBraces = FormatStyle::BS_Mozilla;
+  verifyFormat("namespace a {\n"
+               "class A\n"
+               "{\n"
+               "  void f()\n"
+               "  {\n"
+               "    if (true) {\n"
+               "      a();\n"
+               "      b();\n"
+               "    }\n"
+               "  }\n"
+               "  void g() { return; }\n"
+               "};\n"
+               "enum E\n"
+               "{\n"
+               "  A,\n"
+               "  // foo\n"
+               "  B,\n"
+               "  C\n"
+               "};\n"
+               "struct B\n"
+               "{\n"
+               "  int x;\n"
+               "};\n"
+               "}\n",
+               MozillaBraceStyle);
+  verifyFormat("struct S\n"
+               "{\n"
+               "  int Type;\n"
+               "  union\n"
+               "  {\n"
+               "    int x;\n"
+               "    double y;\n"
+               "  } Value;\n"
+               "  class C\n"
+               "  {\n"
+               "    MyFavoriteType Value;\n"
+               "  } Class;\n"
+               "}\n",
+               MozillaBraceStyle);
+}
+
 TEST_F(FormatTest, StroustrupBraceBreaking) {
   FormatStyle StroustrupBraceStyle = getLLVMStyle();
   StroustrupBraceStyle.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
@@ -9219,6 +9263,8 @@ TEST_F(FormatTest, ParsesConfiguration) {
               FormatStyle::BS_Attach);
   CHECK_PARSE("BreakBeforeBraces: Linux", BreakBeforeBraces,
               FormatStyle::BS_Linux);
+  CHECK_PARSE("BreakBeforeBraces: Mozilla", BreakBeforeBraces,
+              FormatStyle::BS_Mozilla);
   CHECK_PARSE("BreakBeforeBraces: Stroustrup", BreakBeforeBraces,
               FormatStyle::BS_Stroustrup);
   CHECK_PARSE("BreakBeforeBraces: Allman", BreakBeforeBraces,