diff --git a/clang/docs/ClangFormatStyleOptions.rst b/clang/docs/ClangFormatStyleOptions.rst
--- a/clang/docs/ClangFormatStyleOptions.rst
+++ b/clang/docs/ClangFormatStyleOptions.rst
@@ -1719,6 +1719,9 @@
   priority for order.``SortPriority`` is set to the value of ``Priority``
   as default if it is not assigned.
 
+  Each regular expression can be marked as case sensitive with the field
+  ``CaseSensitive``, per default it is not.
+
   To configure this in the .clang-format file, use:
 
   .. code-block:: yaml
@@ -1727,6 +1730,7 @@
       - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
         Priority:        2
         SortPriority:    2
+        CaseSensitive:   true
       - Regex:           '^(<|"(gtest|gmock|isl|json)/)'
         Priority:        3
       - Regex:           '<[[:alnum:].]+>'
diff --git a/clang/include/clang/Tooling/Inclusions/IncludeStyle.h b/clang/include/clang/Tooling/Inclusions/IncludeStyle.h
--- a/clang/include/clang/Tooling/Inclusions/IncludeStyle.h
+++ b/clang/include/clang/Tooling/Inclusions/IncludeStyle.h
@@ -60,8 +60,11 @@
     int Priority;
     /// The custom priority to sort before grouping.
     int SortPriority;
+    /// If the regular expression is case sensitive.
+    bool RegexIsCaseSensitive;
     bool operator==(const IncludeCategory &Other) const {
-      return Regex == Other.Regex && Priority == Other.Priority;
+      return Regex == Other.Regex && Priority == Other.Priority &&
+             RegexIsCaseSensitive == Other.RegexIsCaseSensitive;
     }
   };
 
@@ -84,20 +87,25 @@
   /// (https://llvm.org/docs/CodingStandards.html#include-style). However, you
   /// can also assign negative priorities if you have certain headers that
   /// always need to be first.
-  /// 
+  ///
   /// There is a third and optional field ``SortPriority`` which can used while
-  /// ``IncludeBloks = IBS_Regroup`` to define the priority in which ``#includes``
-  /// should be ordered, and value of ``Priority`` defines the order of
+  /// ``IncludeBloks = IBS_Regroup`` to define the priority in which
+  /// ``#includes`` should be ordered, and value of ``Priority`` defines the
+  /// order of
   /// ``#include blocks`` and also enables to group ``#includes`` of different
   /// priority for order.``SortPriority`` is set to the value of ``Priority``
   /// as default if it is not assigned.
   ///
+  /// Each regular expression can be marked as case sensitive with the field
+  /// ``CaseSensitive``, per default it is not.
+  ///
   /// To configure this in the .clang-format file, use:
   /// \code{.yaml}
   ///   IncludeCategories:
   ///     - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
   ///       Priority:        2
   ///       SortPriority:    2
+  ///       CaseSensitive:   true
   ///     - Regex:           '^(<|"(gtest|gmock|isl|json)/)'
   ///       Priority:        3
   ///     - Regex:           '<[[:alnum:].]+>'
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
@@ -916,9 +916,9 @@
   LLVMStyle.ForEachMacros.push_back("Q_FOREACH");
   LLVMStyle.ForEachMacros.push_back("BOOST_FOREACH");
   LLVMStyle.IncludeStyle.IncludeCategories = {
-      {"^\"(llvm|llvm-c|clang|clang-c)/", 2, 0},
-      {"^(<|\"(gtest|gmock|isl|json)/)", 3, 0},
-      {".*", 1, 0}};
+      {"^\"(llvm|llvm-c|clang|clang-c)/", 2, 0, false},
+      {"^(<|\"(gtest|gmock|isl|json)/)", 3, 0, false},
+      {".*", 1, 0, false}};
   LLVMStyle.IncludeStyle.IncludeIsMainRegex = "(Test)?$";
   LLVMStyle.IncludeStyle.IncludeBlocks = tooling::IncludeStyle::IBS_Preserve;
   LLVMStyle.IndentCaseLabels = false;
@@ -1016,10 +1016,10 @@
   GoogleStyle.AlwaysBreakTemplateDeclarations = FormatStyle::BTDS_Yes;
   GoogleStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = true;
   GoogleStyle.DerivePointerAlignment = true;
-  GoogleStyle.IncludeStyle.IncludeCategories = {{"^<ext/.*\\.h>", 2, 0},
-                                                {"^<.*\\.h>", 1, 0},
-                                                {"^<.*", 2, 0},
-                                                {".*", 3, 0}};
+  GoogleStyle.IncludeStyle.IncludeCategories = {{"^<ext/.*\\.h>", 2, 0, false},
+                                                {"^<.*\\.h>", 1, 0, false},
+                                                {"^<.*", 2, 0, false},
+                                                {".*", 3, 0, false}};
   GoogleStyle.IncludeStyle.IncludeIsMainRegex = "([-_](test|unittest))?$";
   GoogleStyle.IncludeStyle.IncludeBlocks = tooling::IncludeStyle::IBS_Regroup;
   GoogleStyle.IndentCaseLabels = true;
diff --git a/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp b/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp
--- a/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp
+++ b/clang/lib/Tooling/Inclusions/HeaderIncludes.cpp
@@ -190,8 +190,11 @@
 IncludeCategoryManager::IncludeCategoryManager(const IncludeStyle &Style,
                                                StringRef FileName)
     : Style(Style), FileName(FileName) {
-  for (const auto &Category : Style.IncludeCategories)
-    CategoryRegexs.emplace_back(Category.Regex, llvm::Regex::IgnoreCase);
+  for (const auto &Category : Style.IncludeCategories) {
+    CategoryRegexs.emplace_back(Category.Regex, Category.RegexIsCaseSensitive
+                                                    ? llvm::Regex::NoFlags
+                                                    : llvm::Regex::IgnoreCase);
+  }
   IsMainFile = FileName.endswith(".c") || FileName.endswith(".cc") ||
                FileName.endswith(".cpp") || FileName.endswith(".c++") ||
                FileName.endswith(".cxx") || FileName.endswith(".m") ||
diff --git a/clang/lib/Tooling/Inclusions/IncludeStyle.cpp b/clang/lib/Tooling/Inclusions/IncludeStyle.cpp
--- a/clang/lib/Tooling/Inclusions/IncludeStyle.cpp
+++ b/clang/lib/Tooling/Inclusions/IncludeStyle.cpp
@@ -18,6 +18,7 @@
   IO.mapOptional("Regex", Category.Regex);
   IO.mapOptional("Priority", Category.Priority);
   IO.mapOptional("SortPriority", Category.SortPriority);
+  IO.mapOptional("CaseSensitive", Category.RegexIsCaseSensitive);
 }
 
 void ScalarEnumerationTraits<IncludeStyle::IncludeBlocksStyle>::enumeration(
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
@@ -14526,12 +14526,13 @@
 
   Style.IncludeStyle.IncludeCategories.clear();
   std::vector<tooling::IncludeStyle::IncludeCategory> ExpectedCategories = {
-      {"abc/.*", 2, 0}, {".*", 1, 0}};
+      {"abc/.*", 2, 0, false}, {".*", 1, 0, true}};
   CHECK_PARSE("IncludeCategories:\n"
               "  - Regex: abc/.*\n"
               "    Priority: 2\n"
               "  - Regex: .*\n"
-              "    Priority: 1",
+              "    Priority: 1\n"
+              "    CaseSensitive: true\n",
               IncludeStyle.IncludeCategories, ExpectedCategories);
   CHECK_PARSE("IncludeIsMainRegex: 'abc$'", IncludeStyle.IncludeIsMainRegex,
               "abc$");
diff --git a/clang/unittests/Format/SortIncludesTest.cpp b/clang/unittests/Format/SortIncludesTest.cpp
--- a/clang/unittests/Format/SortIncludesTest.cpp
+++ b/clang/unittests/Format/SortIncludesTest.cpp
@@ -72,19 +72,19 @@
 TEST_F(SortIncludesTest, SortedIncludesUsingSortPriorityAttribute) {
   FmtStyle.IncludeStyle.IncludeBlocks = tooling::IncludeStyle::IBS_Regroup;
   FmtStyle.IncludeStyle.IncludeCategories = {
-      {"^<sys/param\\.h>", 1, 0},
-      {"^<sys/types\\.h>", 1, 1},
-      {"^<sys.*/", 1, 2},
-      {"^<uvm/", 2, 3},
-      {"^<machine/", 3, 4},
-      {"^<dev/", 4, 5},
-      {"^<net.*/", 5, 6},
-      {"^<protocols/", 5, 7},
-      {"^<(fs|miscfs|msdosfs|nfs|ntfs|ufs)/", 6, 8},
-      {"^<(x86|amd64|i386|xen)/", 7, 8},
-      {"<path", 9, 11},
-      {"^<[^/].*\\.h>", 8, 10},
-      {"^\".*\\.h\"", 10, 12}};
+      {"^<sys/param\\.h>", 1, 0, false},
+      {"^<sys/types\\.h>", 1, 1, false},
+      {"^<sys.*/", 1, 2, false},
+      {"^<uvm/", 2, 3, false},
+      {"^<machine/", 3, 4, false},
+      {"^<dev/", 4, 5, false},
+      {"^<net.*/", 5, 6, false},
+      {"^<protocols/", 5, 7, false},
+      {"^<(fs|miscfs|msdosfs|nfs|ntfs|ufs)/", 6, 8, false},
+      {"^<(x86|amd64|i386|xen)/", 7, 8, false},
+      {"<path", 9, 11, false},
+      {"^<[^/].*\\.h>", 8, 10, false},
+      {"^\".*\\.h\"", 10, 12, false}};
   EXPECT_EQ("#include <sys/param.h>\n"
             "#include <sys/types.h>\n"
             "#include <sys/ioctl.h>\n"
@@ -600,8 +600,59 @@
                  "a_TEST.cc"));
 }
 
+TEST_F(SortIncludesTest, SupportOptionalCaseSensitiveMachting) {
+  Style.IncludeBlocks = clang::tooling::IncludeStyle::IBS_Regroup;
+  Style.IncludeCategories = {{"^\"", 1, 0, false},
+                             {"^<.*\\.h>$", 2, 0, false},
+                             {"^<Q[A-Z][^\\.]*>", 3, 0, false},
+                             {"^<Qt[^\\.]*>", 4, 0, false},
+                             {"^<", 5, 0, false}};
+
+  StringRef UnsortedCode = "#include <QWidget>\n"
+                           "#include \"qt.h\"\n"
+                           "#include <algorithm>\n"
+                           "#include <windows.h>\n"
+                           "#include <QLabel>\n"
+                           "#include \"qa.h\"\n"
+                           "#include <queue>\n"
+                           "#include <qtwhatever.h>\n"
+                           "#include <QtGlobal>\n";
+
+  EXPECT_EQ("#include \"qa.h\"\n"
+            "#include \"qt.h\"\n"
+            "\n"
+            "#include <qtwhatever.h>\n"
+            "#include <windows.h>\n"
+            "\n"
+            "#include <QLabel>\n"
+            "#include <QWidget>\n"
+            "#include <QtGlobal>\n"
+            "#include <queue>\n"
+            "\n"
+            "#include <algorithm>\n",
+            sort(UnsortedCode));
+
+  Style.IncludeCategories[2].RegexIsCaseSensitive = true;
+  Style.IncludeCategories[3].RegexIsCaseSensitive = true;
+  EXPECT_EQ("#include \"qa.h\"\n"
+            "#include \"qt.h\"\n"
+            "\n"
+            "#include <qtwhatever.h>\n"
+            "#include <windows.h>\n"
+            "\n"
+            "#include <QLabel>\n"
+            "#include <QWidget>\n"
+            "\n"
+            "#include <QtGlobal>\n"
+            "\n"
+            "#include <algorithm>\n"
+            "#include <queue>\n",
+            sort(UnsortedCode));
+}
+
 TEST_F(SortIncludesTest, NegativePriorities) {
-  Style.IncludeCategories = {{".*important_os_header.*", -1, 0}, {".*", 1, 0}};
+  Style.IncludeCategories = {{".*important_os_header.*", -1, 0, false},
+                             {".*", 1, 0, false}};
   EXPECT_EQ("#include \"important_os_header.h\"\n"
             "#include \"c_main.h\"\n"
             "#include \"a_other.h\"\n",
@@ -621,7 +672,8 @@
 }
 
 TEST_F(SortIncludesTest, PriorityGroupsAreSeparatedWhenRegroupping) {
-  Style.IncludeCategories = {{".*important_os_header.*", -1, 0}, {".*", 1, 0}};
+  Style.IncludeCategories = {{".*important_os_header.*", -1, 0, false},
+                             {".*", 1, 0, false}};
   Style.IncludeBlocks = tooling::IncludeStyle::IBS_Regroup;
 
   EXPECT_EQ("#include \"important_os_header.h\"\n"