diff --git a/clang/lib/Driver/Job.cpp b/clang/lib/Driver/Job.cpp
--- a/clang/lib/Driver/Job.cpp
+++ b/clang/lib/Driver/Job.cpp
@@ -107,9 +107,26 @@
   }
 
   // Quote and escape. This isn't really complete, but good enough.
+  // On Windows, the backslash is the path separator, and escaping the backslash
+  // results in unnatural-looking output that's also inconsistent with how paths
+  // are printed out elsewhere (e.g. when printing out the installation
+  // directory). Windows native shells (cmd and PowerShell) use different escape
+  // characters so escaping the backslash is unnecessary.  bash (the most common
+  // non-native shell on Windows) uses backslash as an escape character inside
+  // double quotes only when it's followed by $, `, ", \, or a literal newline;
+  // the last three are disallowed in paths on Windows and the first two are
+  // unlikely, so this shouldn't cause issues in practice. Note that we always
+  // enclose an argument containing backslashes in quotes even if we aren't
+  // escaping the backslashes, since bash always interprets it as an escape
+  // character outside quotes.
+#if defined(_WIN32)
+  constexpr bool RunningOnWindows = true;
+#else
+  constexpr bool RunningOnWindows = false;
+#endif
   OS << '"';
   for (const auto c : Arg) {
-    if (c == '"' || c == '\\' || c == '$')
+    if (c == '"' || (c == '\\' && !RunningOnWindows) || c == '$')
       OS << '\\';
     OS << c;
   }
diff --git a/clang/test/Driver/backslash.c b/clang/test/Driver/backslash.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/backslash.c
@@ -0,0 +1,6 @@
+// RUN: %clang -fsyntax-only %s -### 2>&1 | FileCheck %s
+// Ensure the treatment of backslashes is consistent in the printed InstalledDir
+// and commands. We would previous escape backslashes in the printed commands
+// but not in the printed InstallDir, causing the match to fail.
+// CHECK: InstalledDir: [[INSTALLEDDIR:.+$]]
+// CHECK: "[[INSTALLEDDIR]]{{[/\\]}}clang