diff --git a/runtime/tools/compiler_layering_check.py b/runtime/tools/compiler_layering_check.py
index 06d73d98fd3..e8c955a0ee0 100755
--- a/runtime/tools/compiler_layering_check.py
+++ b/runtime/tools/compiler_layering_check.py
@@ -10,7 +10,6 @@
 # Currently it only checks that core runtime headers RUNTIME_LAYER_HEADERS
 # are not included into any sources listed in SHOULD_NOT_DEPEND_ON_RUNTIME.
 
-import glob
 import os
 import re
 import sys
@@ -107,7 +106,7 @@ class LayeringChecker(object):
     def ExtractIncludes(self, file):
         """Extract the list of includes from the given file."""
         deps = set()
-        with open(os.path.join(self.root, file)) as file:
+        with open(os.path.join(self.root, file), encoding='utf-8') as file:
             for line in file:
                 if line.startswith('namespace dart {'):
                     break
diff --git a/runtime/tools/embedder_layering_check.py b/runtime/tools/embedder_layering_check.py
index 775040e5987..5e564d16cad 100644
--- a/runtime/tools/embedder_layering_check.py
+++ b/runtime/tools/embedder_layering_check.py
@@ -7,7 +7,6 @@
 # Simple tool for verifying that sources from the standalone embedder do not
 # directly include sources from the VM or vice versa.
 
-import glob
 import os
 import re
 import sys
@@ -28,7 +27,7 @@ EXTRA_TEST_FILES = [
 
 def CheckFile(sdk_root, path):
     includes = set()
-    with open(os.path.join(sdk_root, path)) as file:
+    with open(os.path.join(sdk_root, path), encoding='utf-8') as file:
         for line in file:
             m = INCLUDE_DIRECTIVE_RE.match(line)
             if m is not None: