diff --git a/tools/patman/func_test.py b/tools/patman/func_test.py
index 2321f9e028be7623469fc179035c873d27e21f34..76319fff37e3df6f0fc3bd515c92209470658ce1 100644
--- a/tools/patman/func_test.py
+++ b/tools/patman/func_test.py
@@ -51,7 +51,7 @@ class TestFunctional(unittest.TestCase):
 
     @classmethod
     def GetText(self, fname):
-        return open(self.GetPath(fname)).read()
+        return open(self.GetPath(fname), encoding='utf-8').read()
 
     @classmethod
     def GetPatchName(self, subject):
@@ -160,7 +160,7 @@ class TestFunctional(unittest.TestCase):
                     dry_run, not ignore_bad_tags, cc_file,
                     in_reply_to=in_reply_to, thread=None)
             series.ShowActions(args, cmd, process_tags)
-        cc_lines = open(cc_file).read().splitlines()
+        cc_lines = open(cc_file, encoding='utf-8').read().splitlines()
         os.remove(cc_file)
 
         lines = out[0].splitlines()
@@ -229,14 +229,14 @@ Simon Glass (2):
 2.7.4
 
 '''
-        lines = open(cover_fname).read().splitlines()
+        lines = open(cover_fname, encoding='utf-8').read().splitlines()
         self.assertEqual(
                 'Subject: [RFC PATCH v3 0/2] test: A test patch series',
                 lines[3])
         self.assertEqual(expected.splitlines(), lines[7:])
 
         for i, fname in enumerate(args):
-            lines = open(fname).read().splitlines()
+            lines = open(fname, encoding='utf-8').read().splitlines()
             subject = [line for line in lines if line.startswith('Subject')]
             self.assertEqual('Subject: [RFC %d/%d]' % (i + 1, count),
                              subject[0][:18])
diff --git a/tools/patman/patchstream.py b/tools/patman/patchstream.py
index ef06606297954aec0392f03c90619cd6a27aae2a..df3eb7483bb2f5f95770bc7d2d1ae24fe059d21f 100644
--- a/tools/patman/patchstream.py
+++ b/tools/patman/patchstream.py
@@ -511,8 +511,8 @@ def FixPatch(backup_dir, fname, series, commit):
         A list of errors, or [] if all ok.
     """
     handle, tmpname = tempfile.mkstemp()
-    outfd = os.fdopen(handle, 'w')
-    infd = open(fname, 'r')
+    outfd = os.fdopen(handle, 'w', encoding='utf-8')
+    infd = open(fname, 'r', encoding='utf-8')
     ps = PatchStream(series)
     ps.commit = commit
     ps.ProcessStream(infd, outfd)
diff --git a/tools/patman/series.py b/tools/patman/series.py
index d667d9b6d61c257ad33759e25b619fd6ee259d85..02a1113ad017ba6079c0ad4e480529ee8c0c22cf 100644
--- a/tools/patman/series.py
+++ b/tools/patman/series.py
@@ -223,7 +223,7 @@ class Series(dict):
         col = terminal.Color()
         # Look for commit tags (of the form 'xxx:' at the start of the subject)
         fname = '/tmp/patman.%d' % os.getpid()
-        fd = open(fname, 'w')
+        fd = open(fname, 'w', encoding='utf-8')
         all_ccs = []
         for commit in self.commits:
             cc = []
diff --git a/tools/patman/settings.py b/tools/patman/settings.py
index c98911d522b4e4de05d1a1dfb1858d6dc903f747..5dc83a850023c779d6ce76ce96aaea9df3056646 100644
--- a/tools/patman/settings.py
+++ b/tools/patman/settings.py
@@ -165,7 +165,7 @@ def ReadGitAliases(fname):
         fname: Filename to read
     """
     try:
-        fd = open(fname, 'r')
+        fd = open(fname, 'r', encoding='utf-8')
     except IOError:
         print("Warning: Cannot find alias file '%s'" % fname)
         return
@@ -259,7 +259,7 @@ def _ReadAliasFile(fname):
     """
     if os.path.exists(fname):
         bad_line = None
-        with open(fname) as fd:
+        with open(fname, encoding='utf-8') as fd:
             linenum = 0
             for line in fd:
                 linenum += 1
diff --git a/tools/patman/test.py b/tools/patman/test.py
index cc61c20606e8eb1f65d208f2166bb7a633b84aec..889e186606ea5e6bbe429dcaccc784bd04d8512b 100644
--- a/tools/patman/test.py
+++ b/tools/patman/test.py
@@ -72,12 +72,12 @@ Signed-off-by: Simon Glass <sjg@chromium.org>
 '''
         out = ''
         inhandle, inname = tempfile.mkstemp()
-        infd = os.fdopen(inhandle, 'w')
+        infd = os.fdopen(inhandle, 'w', encoding='utf-8')
         infd.write(data)
         infd.close()
 
         exphandle, expname = tempfile.mkstemp()
-        expfd = os.fdopen(exphandle, 'w')
+        expfd = os.fdopen(exphandle, 'w', encoding='utf-8')
         expfd.write(expected)
         expfd.close()