diff --git a/tests/test-runner/bin/test-runner.py.in b/tests/test-runner/bin/test-runner.py.in
index 5bf13f5c0..2158208be 100755
--- a/tests/test-runner/bin/test-runner.py.in
+++ b/tests/test-runner/bin/test-runner.py.in
@@ -15,6 +15,7 @@
 #
 # Copyright (c) 2012, 2018 by Delphix. All rights reserved.
 # Copyright (c) 2019 Datto Inc.
+# Copyright (c) 2025, Klara, Inc.
 #
 # This script must remain compatible with Python 3.6+.
 #
@@ -372,6 +373,8 @@ User: %s
         stdout/stderr/merged in its own file.
         """
 
+        timeprefix = datetime.now().strftime('[%FT%T.%f] ')
+
         logname = getpwuid(os.getuid()).pw_name
         rer = ''
         if self.reran is True:
@@ -383,7 +386,7 @@ User: %s
             msga = 'Test: %s%s ' % (self.pathname, user)
         msgb = '[%s] [%s]%s\n' % (self.result.runtime, self.result.result, rer)
         pad = ' ' * (80 - (len(msga) + len(msgb)))
-        result_line = msga + pad + msgb
+        result_line = timeprefix + msga + pad + msgb
 
         # The result line is always written to the log file. If -q was
         # specified only failures are written to the console, otherwise
diff --git a/tests/test-runner/bin/zts-report.py.in b/tests/test-runner/bin/zts-report.py.in
index 40f5083d1..001970120 100755
--- a/tests/test-runner/bin/zts-report.py.in
+++ b/tests/test-runner/bin/zts-report.py.in
@@ -15,6 +15,7 @@
 #
 # Copyright (c) 2017 by Delphix. All rights reserved.
 # Copyright (c) 2018 by Lawrence Livermore National Security, LLC.
+# Copyright (c) 2025, Klara, Inc.
 #
 # This script must remain compatible with Python 3.6+.
 #
@@ -381,7 +382,8 @@ def process_results(pathname):
 
     prefix = '/zfs-tests/tests/(?:functional|perf/regression)/'
     pattern = \
-        r'^Test(?:\s+\(\S+\))?:' + \
+        r'^(?:\[[0-9\-T:\.]+\]\s+)?' + \
+        r'Test(?:\s+\(\S+\))?:' + \
         rf'\s*\S*{prefix}(\S+)' + \
         r'\s*\(run as (\S+)\)\s*\[(\S+)\]\s*\[(\S+)\]'
     pattern_log = r'^\s*Log directory:\s*(\S*)'
diff --git a/tests/test-runner/include/logapi.shlib b/tests/test-runner/include/logapi.shlib
index 670ecfefb..29e0c7f1c 100644
--- a/tests/test-runner/include/logapi.shlib
+++ b/tests/test-runner/include/logapi.shlib
@@ -25,6 +25,7 @@
 # Use is subject to license terms.
 #
 # Copyright (c) 2012, 2020 by Delphix. All rights reserved.
+# Copyright (c) 2025, Klara, Inc.
 #
 
 STF_PASS=0
@@ -465,7 +466,11 @@ function _endlog
 
 function _printline
 {
-	echo "$@"
+	if [[ -n "$ZTS_LOG_SUPPRESS_TIMESTAMP" ]] ; then
+		printf '[%(%FT%T.%6N)T] %s\n' now "$*"
+	else
+		echo "$@"
+	fi
 }
 
 # Output an error message
diff --git a/tests/zfs-tests/callbacks/zfs_dmesg.ksh b/tests/zfs-tests/callbacks/zfs_dmesg.ksh
index 73c654125..de31765a5 100755
--- a/tests/zfs-tests/callbacks/zfs_dmesg.ksh
+++ b/tests/zfs-tests/callbacks/zfs_dmesg.ksh
@@ -15,6 +15,7 @@
 #
 # Copyright (c) 2016 by Delphix. All rights reserved.
 # Copyright (c) 2017 Lawrence Livermore National Security, LLC.
+# Copyright (c) 2025, Klara, Inc.
 #
 
 # $1: number of lines to output (default: 200)
@@ -25,7 +26,11 @@ echo " Tailing last $lines lines of dmesg log"
 echo "================================================================="
 
 # report and reset afterwards
-sudo dmesg -c | tail -n $lines
+dmesg_args="-c"
+if [[ $(uname) = "Linux" ]] ; then
+	dmesg_args="$dmesg_args --time-format=iso"
+fi
+sudo dmesg $dmesg_args | tail -n $lines
 
 echo "================================================================="
 echo " End of dmesg log"
diff --git a/tests/zfs-tests/include/libtest.shlib b/tests/zfs-tests/include/libtest.shlib
index 8bffe9d82..d8e7bb73e 100644
--- a/tests/zfs-tests/include/libtest.shlib
+++ b/tests/zfs-tests/include/libtest.shlib
@@ -2884,7 +2884,9 @@ function user_run
 	typeset out=$TEST_BASE_DIR/out
 	typeset err=$TEST_BASE_DIR/err
 
-	sudo -Eu $user env PATH="$PATH" ksh <<<"$*" >$out 2>$err
+	sudo -Eu $user \
+	    env PATH="$PATH" ZTS_LOG_SUPPRESS_TIMESTAMP=1 \
+	    ksh <<<"$*" >$out 2>$err
 	typeset res=$?
 	log_note "out: $(<$out)"
 	log_note "err: $(<$err)"