diff --git a/clang/docs/ClangFormatStyleOptions.rst b/clang/docs/ClangFormatStyleOptions.rst
--- a/clang/docs/ClangFormatStyleOptions.rst
+++ b/clang/docs/ClangFormatStyleOptions.rst
@@ -2615,6 +2615,19 @@
         }
      }
 
+**PPIndentWidth** (``unsigned``)
+  The number of columns to use for indentation of preprocessor statements.
+
+  .. code-block:: c++
+
+     PPIndentWidth: 1
+
+     #ifdef __linux__
+     # define FOO
+     #else
+     # define BAR
+     #endif
+
 **IndentWrappedFunctionNames** (``bool``)
   Indent if a function definition or declaration is wrapped after the
   type.
diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -2323,6 +2323,18 @@
   /// \endcode
   unsigned IndentWidth;
 
+  /// The number of columns to use for indentation of preprocessor statements.
+  /// \code
+  ///    PPIndentWidth: 1
+  ///
+  ///    #ifdef __linux__
+  ///    # define FOO
+  ///    #else
+  ///    # define BAR
+  ///    #endif
+  /// \endcode
+  unsigned PPIndentWidth;
+
   /// Indent if a function definition or declaration is wrapped after the
   /// type.
   /// \code
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -664,6 +664,7 @@
     IO.mapOptional("PenaltyIndentedWhitespace",
                    Style.PenaltyIndentedWhitespace);
     IO.mapOptional("PointerAlignment", Style.PointerAlignment);
+    IO.mapOptional("PPIndentWidth", Style.PPIndentWidth);
     IO.mapOptional("RawStringFormats", Style.RawStringFormats);
     IO.mapOptional("ReflowComments", Style.ReflowComments);
     IO.mapOptional("ShortNamespaceLines", Style.ShortNamespaceLines);
@@ -1021,6 +1022,7 @@
   LLVMStyle.IndentRequires = false;
   LLVMStyle.IndentWrappedFunctionNames = false;
   LLVMStyle.IndentWidth = 2;
+  LLVMStyle.PPIndentWidth = 2; // default to old value
   LLVMStyle.InsertTrailingCommas = FormatStyle::TCS_None;
   LLVMStyle.JavaScriptQuotes = FormatStyle::JSQS_Leave;
   LLVMStyle.JavaScriptWrapImports = true;
@@ -1263,6 +1265,7 @@
     ChromiumStyle.BreakAfterJavaFieldAnnotations = true;
     ChromiumStyle.ContinuationIndentWidth = 8;
     ChromiumStyle.IndentWidth = 4;
+    ChromiumStyle.PPIndentWidth = 4; // default to old value
     // See styleguide for import groups:
     // https://chromium.googlesource.com/chromium/src/+/master/styleguide/java/java.md#Import-Order
     ChromiumStyle.JavaImportGroups = {
@@ -1309,6 +1312,7 @@
   MozillaStyle.BreakInheritanceList = FormatStyle::BILS_BeforeComma;
   MozillaStyle.ConstructorInitializerIndentWidth = 2;
   MozillaStyle.ContinuationIndentWidth = 2;
+  MozillaStyle.PPIndentWidth = 2; // default to old value
   MozillaStyle.Cpp11BracedListStyle = false;
   MozillaStyle.FixNamespaceComments = false;
   MozillaStyle.IndentCaseLabels = true;
@@ -1334,6 +1338,7 @@
   Style.ColumnLimit = 0;
   Style.FixNamespaceComments = false;
   Style.IndentWidth = 4;
+  Style.PPIndentWidth = 4; // default to old value
   Style.NamespaceIndentation = FormatStyle::NI_Inner;
   Style.ObjCBlockIndentWidth = 4;
   Style.ObjCSpaceAfterProperty = true;
@@ -1363,6 +1368,7 @@
   Style.ColumnLimit = 120;
   Style.TabWidth = 4;
   Style.IndentWidth = 4;
+  Style.PPIndentWidth = 4; // default to old value
   Style.UseTab = FormatStyle::UT_Never;
   Style.BreakBeforeBraces = FormatStyle::BS_Custom;
   Style.BraceWrapping.AfterClass = true;
diff --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -57,7 +57,7 @@
     while (IndentForLevel.size() <= Line.Level)
       IndentForLevel.push_back(-1);
     if (Line.InPPDirective) {
-      Indent = Line.Level * Style.IndentWidth + AdditionalIndent;
+      Indent = Line.Level * Style.PPIndentWidth + AdditionalIndent;
     } else {
       IndentForLevel.resize(Line.Level + 1);
       Indent = getIndent(IndentForLevel, Line.Level);
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -3432,6 +3432,18 @@
 }
 
 TEST_F(FormatTest, IndentsPPDirectiveInReducedSpace) {
+  FormatStyle style = getLLVMStyleWithColumns(4);
+  style.PPIndentWidth = 1;
+
+  verifyFormat("#ifdef __linux__\n"
+               "# define FOO\n"
+               "#endif"
+               "void foo()\n"
+               "{\n"
+               "    int x = 0;\n"
+               "}\n",
+               style);
+
   verifyFormat("#define A(BB)", getLLVMStyleWithColumns(13));
   verifyFormat("#define A( \\\n    BB)", getLLVMStyleWithColumns(12));
   verifyFormat("#define A( \\\n    A, B)", getLLVMStyleWithColumns(12));