diff --git a/llvm/utils/lit/lit/TestRunner.py b/llvm/utils/lit/lit/TestRunner.py
--- a/llvm/utils/lit/lit/TestRunner.py
+++ b/llvm/utils/lit/lit/TestRunner.py
@@ -1081,9 +1081,7 @@
         tmpDir = tmpDir.replace('\\', '/')
         tmpBase = tmpBase.replace('\\', '/')
 
-    # We use #_MARKER_# to hide %% while we do the other substitutions.
     substitutions = []
-    substitutions.extend([('%%', '#_MARKER_#')])
     substitutions.extend(test.config.substitutions)
     tmpName = tmpBase + '.tmp'
     baseName = os.path.basename(tmpBase)
@@ -1093,8 +1091,7 @@
                           ('%{pathsep}', os.pathsep),
                           ('%t', tmpName),
                           ('%basename_t', baseName),
-                          ('%T', tmpDir),
-                          ('#_MARKER_#', '%')])
+                          ('%T', tmpDir)])
 
     # "%/[STpst]" should be normalized.
     substitutions.extend([
@@ -1159,6 +1156,14 @@
     `recursion_limit` times, it is an error. If the `recursion_limit` is
     `None` (the default), no recursive substitution is performed at all.
     """
+
+    # We use #_MARKER_# to hide %% while we do the other substitutions.
+    def escape(ln):
+        return _caching_re_compile('%%').sub('#_MARKER_#', ln)
+
+    def unescape(ln):
+        return _caching_re_compile('#_MARKER_#').sub('%', ln)
+
     def processLine(ln):
         # Apply substitutions
         for a,b in substitutions:
@@ -1171,7 +1176,7 @@
             # short-lived, since the set of substitutions is fairly small, and
             # since thrashing has such bad consequences, not bounding the cache
             # seems reasonable.
-            ln = _caching_re_compile(a).sub(str(b), ln)
+            ln = _caching_re_compile(a).sub(str(b), escape(ln))
 
         # Strip the trailing newline and any extra whitespace.
         return ln.strip()
@@ -1193,10 +1198,9 @@
 
         return processed
 
-    # Note Python 3 map() gives an iterator rather than a list so explicitly
-    # convert to list before returning.
     process = processLine if recursion_limit is None else processLineToFixedPoint
-    return list(map(process, script))
+    
+    return [unescape(process(ln)) for ln in script]
 
 
 class ParserKind(object):
diff --git a/llvm/utils/lit/tests/Inputs/shtest-recursive-substitution/escaping/lit.cfg b/llvm/utils/lit/tests/Inputs/shtest-recursive-substitution/escaping/lit.cfg
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/shtest-recursive-substitution/escaping/lit.cfg
@@ -0,0 +1,10 @@
+import lit.formats
+config.name = 'escaping'
+config.suffixes = ['.py']
+config.test_format = lit.formats.ShTest()
+config.test_source_root = None
+config.test_exec_root = None
+
+config.substitutions = [("%rec1", "%%s"), ("%rec2", "%rec1")]
+
+config.recursiveExpansionLimit = 5
diff --git a/llvm/utils/lit/tests/Inputs/shtest-recursive-substitution/escaping/test.py b/llvm/utils/lit/tests/Inputs/shtest-recursive-substitution/escaping/test.py
new file mode 100644
--- /dev/null
+++ b/llvm/utils/lit/tests/Inputs/shtest-recursive-substitution/escaping/test.py
@@ -0,0 +1 @@
+# RUN: echo %rec2 %%s %%%%s
diff --git a/llvm/utils/lit/tests/shtest-recursive-substitution.py b/llvm/utils/lit/tests/shtest-recursive-substitution.py
--- a/llvm/utils/lit/tests/shtest-recursive-substitution.py
+++ b/llvm/utils/lit/tests/shtest-recursive-substitution.py
@@ -21,3 +21,7 @@
 
 # RUN: %{lit} -j 1 %{inputs}/shtest-recursive-substitution/set-to-none --show-all | FileCheck --check-prefix=CHECK-TEST6 %s
 # CHECK-TEST6: PASS: set-to-none :: test.py
+
+# RUN: %{lit} -j 1 %{inputs}/shtest-recursive-substitution/escaping --show-all | FileCheck --check-prefix=CHECK-TEST7 %s
+# CHECK-TEST7: PASS: escaping :: test.py
+# CHECK-TEST7: $ "echo" "%s" "%s" "%%s"