Index: llvm/utils/lit/lit/TestRunner.py
===================================================================
--- llvm/utils/lit/lit/TestRunner.py
+++ llvm/utils/lit/lit/TestRunner.py
@@ -1133,9 +1133,12 @@
 
     # Write script file
     mode = 'w'
+    open_kwargs = {}
     if litConfig.isWindows and not isWin32CMDEXE:
-      mode += 'b'  # Avoid CRLFs when writing bash scripts.
-    f = open(script, mode)
+        mode += 'b'  # Avoid CRLFs when writing bash scripts.
+    elif sys.version_info > (3,0):
+        open_kwargs['encoding'] = 'utf-8'
+    f = open(script, mode, **open_kwargs)
     if isWin32CMDEXE:
         for i, ln in enumerate(commands):
             commands[i] = re.sub(kPdbgRegex, "echo '\\1' > nul && ", ln)
Index: llvm/utils/lit/tests/Inputs/shtest-format/external_shell/utf8_command.txt
===================================================================
--- /dev/null
+++ llvm/utils/lit/tests/Inputs/shtest-format/external_shell/utf8_command.txt
@@ -0,0 +1,3 @@
+# Run a command including UTF-8 characters.
+#
+# RUN: echo £
Index: llvm/utils/lit/tests/shtest-format.py
===================================================================
--- llvm/utils/lit/tests/shtest-format.py
+++ llvm/utils/lit/tests/shtest-format.py
@@ -80,7 +80,7 @@
 # CHECK: shtest-format :: external_shell/fail_with_bad_encoding.txt
 # CHECK: shtest-format :: fail.txt
 
-# CHECK: Expected Passes    : 7
+# CHECK: Expected Passes    : 8
 # CHECK: Expected Failures  : 4
 # CHECK: Unsupported Tests  : 5
 # CHECK: Unresolved Tests   : 3
@@ -90,7 +90,7 @@
 
 # XUNIT: <?xml version="1.0" encoding="UTF-8" ?>
 # XUNIT-NEXT: <testsuites>
-# XUNIT-NEXT: <testsuite name="shtest-format" tests="23" failures="7" skipped="5">
+# XUNIT-NEXT: <testsuite name="shtest-format" tests="24" failures="7" skipped="5">
 
 # XUNIT: <testcase classname="shtest-format.shtest-format" name="argv0.txt" time="{{[0-9]+\.[0-9]+}}"/>