diff --git a/test/functional/test_framework/test_node.py b/test/functional/test_framework/test_node.py
index 8b2006a05..b9d1082dd 100755
--- a/test/functional/test_framework/test_node.py
+++ b/test/functional/test_framework/test_node.py
@@ -80,10 +80,14 @@ class TestNode():
         # For those callers that need more flexibility, they can just set the args property directly.
         # Note that common args are set in the config file (see initialize_datadir)
         self.extra_args = extra_args
+        # Configuration for logging is set as command-line args rather than in the bitcoin.conf file.
+        # This means that starting a bitcoind using the temp dir to debug a failed test won't
+        # spam debug.log.
         self.args = [
             self.binary,
             "-datadir=" + self.datadir,
             "-logtimemicros",
+            "-logthreadnames",
             "-debug",
             "-debugexclude=libevent",
             "-debugexclude=leveldb",