diff --git a/test/functional/combine_logs.py b/test/functional/combine_logs.py
index d1bf9206b..91b6415a7 100755
--- a/test/functional/combine_logs.py
+++ b/test/functional/combine_logs.py
@@ -63,7 +63,7 @@ def get_log_events(source, logfile):
     Log events may be split over multiple lines. We use the timestamp
     regex match as the marker for a new log event."""
     try:
-        with open(logfile, 'r') as infile:
+        with open(logfile, 'r', encoding='utf-8') as infile:
             event = ''
             timestamp = ''
             for line in infile:
diff --git a/test/functional/test_framework/test_framework.py b/test/functional/test_framework/test_framework.py
index 75a898679..5c2555c1f 100755
--- a/test/functional/test_framework/test_framework.py
+++ b/test/functional/test_framework/test_framework.py
@@ -359,7 +359,7 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
         self.log = logging.getLogger('TestFramework')
         self.log.setLevel(logging.DEBUG)
         # Create file handler to log all messages
-        fh = logging.FileHandler(self.options.tmpdir + '/test_framework.log')
+        fh = logging.FileHandler(self.options.tmpdir + '/test_framework.log', encoding='utf-8')
         fh.setLevel(logging.DEBUG)
         # Create console handler to log messages to stderr. By default this logs only error messages, but can be configured with --loglevel.
         ch = logging.StreamHandler(sys.stdout)