diff --git a/zenmap/zenmapCore/Diff.py b/zenmap/zenmapCore/Diff.py
index 070f5f48c..13e4c4b94 100644
--- a/zenmap/zenmapCore/Diff.py
+++ b/zenmap/zenmapCore/Diff.py
@@ -121,7 +121,7 @@ class NdiffCommand(subprocess.Popen):
                 filename_b
                 ]
         self.stdout_file = tempfile.TemporaryFile(
-                mode="r",
+                mode="r", encoding="utf-8",
                 prefix=APP_NAME + "-ndiff-",
                 suffix=".xml"
                 )
@@ -131,7 +131,7 @@ class NdiffCommand(subprocess.Popen):
         subprocess.Popen.__init__(
                 self,
                 command_list,
-                universal_newlines=True,
+                universal_newlines=True, encoding="utf-8",
                 stdout=self.stdout_file,
                 stderr=subprocess.PIPE,
                 env=env,
diff --git a/zenmap/zenmapCore/NmapCommand.py b/zenmap/zenmapCore/NmapCommand.py
index 941afcdcf..3fe98d7c1 100644
--- a/zenmap/zenmapCore/NmapCommand.py
+++ b/zenmap/zenmapCore/NmapCommand.py
@@ -198,7 +198,7 @@ class NmapCommand(object):
         # We don't need a file name for stdout output, just a handle. A
         # TemporaryFile is deleted as soon as it is closed, and in Unix is
         # unlinked immediately after creation so it's not even visible.
-        f = tempfile.TemporaryFile(mode="r", prefix=APP_NAME + "-stdout-")
+        f = tempfile.TemporaryFile(mode="r", prefix=APP_NAME + "-stdout-", encoding="utf-8")
         self.stdout_file = f
         if stderr is None:
             stderr = f
@@ -223,7 +223,7 @@ class NmapCommand(object):
                 startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
 
         self.command_process = subprocess.Popen(command_list, bufsize=1,
-                                     universal_newlines=True,
+                                     universal_newlines=True, encoding="utf-8",
                                      stdin=subprocess.PIPE,
                                      stdout=f,
                                      stderr=stderr,
diff --git a/zenmap/zenmapGUI/ScriptInterface.py b/zenmap/zenmapGUI/ScriptInterface.py
index 3afd2ebaa..e9d3a065f 100644
--- a/zenmap/zenmapGUI/ScriptInterface.py
+++ b/zenmap/zenmapGUI/ScriptInterface.py
@@ -226,7 +226,8 @@ class ScriptInterface:
         # Separate stderr to avoid breaking XML parsing with "Warning: File
         # ./nse_main.lua exists, but Nmap is using...".
         stderr = tempfile.TemporaryFile(
-                mode="r", prefix=APP_NAME + "-script-help-stderr-")
+                mode="r", prefix=APP_NAME + "-script-help-stderr-",
+                encoding="utf-8")
         log.debug("Script interface: running %s" % repr(command_string))
         nmap_process = NmapCommand(command_string)
         try: