diff --git a/t/0010-basic.t b/t/0010-basic.t
index 9294babc..1709c3f1 100755
--- a/t/0010-basic.t
+++ b/t/0010-basic.t
@@ -84,4 +84,8 @@ test_expect_unstable 'check logfile for replay' '
     grep "Replayed credential" "${MUNGE_LOGFILE}"
 '
 
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0011-munged-cmdline.t b/t/0011-munged-cmdline.t
index 95a1dc79..2566ce05 100755
--- a/t/0011-munged-cmdline.t
+++ b/t/0011-munged-cmdline.t
@@ -65,4 +65,10 @@ test_expect_failure 'finish writing tests' '
     false
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0012-munge-cmdline.t b/t/0012-munge-cmdline.t
index ed878e20..b927e412 100755
--- a/t/0012-munge-cmdline.t
+++ b/t/0012-munge-cmdline.t
@@ -615,4 +615,8 @@ test_expect_success 'stop munged' '
     munged_stop_daemon
 '
 
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0013-unmunge-cmdline.t b/t/0013-unmunge-cmdline.t
index 07ce8eb1..119b8b6c 100755
--- a/t/0013-unmunge-cmdline.t
+++ b/t/0013-unmunge-cmdline.t
@@ -229,4 +229,8 @@ test_expect_success 'stop munged' '
     munged_stop_daemon
 '
 
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0021-munged-valgrind.t b/t/0021-munged-valgrind.t
index fb0dc563..071be97b 100755
--- a/t/0021-munged-valgrind.t
+++ b/t/0021-munged-valgrind.t
@@ -40,4 +40,8 @@ test_expect_success 'check valgrind log for errors in munged' '
     valgrind_check_log
 '
 
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0022-munge-valgrind.t b/t/0022-munge-valgrind.t
index 9e62bdb1..ed9a7d29 100755
--- a/t/0022-munge-valgrind.t
+++ b/t/0022-munge-valgrind.t
@@ -32,4 +32,8 @@ test_expect_success 'check valgrind log for errors in munge' '
     valgrind_check_log
 '
 
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0023-unmunge-valgrind.t b/t/0023-unmunge-valgrind.t
index e54fbbd1..6788ee43 100755
--- a/t/0023-unmunge-valgrind.t
+++ b/t/0023-unmunge-valgrind.t
@@ -36,4 +36,8 @@ test_expect_success 'check valgrind log for errors in unmunge' '
     valgrind_check_log
 '
 
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0100-munged-lock.t b/t/0100-munged-lock.t
index a1ab934a..117e8480 100755
--- a/t/0100-munged-lock.t
+++ b/t/0100-munged-lock.t
@@ -53,7 +53,7 @@ test_expect_success 'check lockfile permissions' '
 #   The lockfile should prevent this.
 ##
 test_expect_success 'start munged with in-use socket' '
-    test_must_fail munged_start_daemon &&
+    test_must_fail munged_start_daemon t-keep-process &&
     egrep "Error:.* Failed to lock \"${MUNGE_LOCKFILE}\"" "${MUNGE_LOGFILE}"
 '
 
@@ -201,4 +201,10 @@ test_expect_success SUDO 'stop unprivileged munged as root' '
     fi
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0101-munged-security-socket.t b/t/0101-munged-security-socket.t
index 560e4ac4..532dc198 100755
--- a/t/0101-munged-security-socket.t
+++ b/t/0101-munged-security-socket.t
@@ -213,11 +213,13 @@ test_expect_success 'socket dir inaccessible by all override' '
             "${MUNGE_LOGFILE}"
 '
 
-# Cleanup detritus from testing.
+# Clean up detritus from testing.  This may include an errant munged process
+#   that has not terminated.
 ##
 test_expect_success 'cleanup' '
     rmdir "${MUNGE_SOCKETDIR}" &&
-    if rmdir "$(dirname "${MUNGE_SOCKETDIR}")" 2>/dev/null; then :; fi
+    if rmdir "$(dirname "${MUNGE_SOCKETDIR}")" 2>/dev/null; then :; fi &&
+    munged_cleanup
 '
 
 test_done
diff --git a/t/0102-munged-security-keyfile.t b/t/0102-munged-security-keyfile.t
index 25e7ce28..5cc18089 100755
--- a/t/0102-munged-security-keyfile.t
+++ b/t/0102-munged-security-keyfile.t
@@ -358,4 +358,10 @@ test_expect_success 'keyfile dir writable by other with sticky bit' '
     chmod 0755 "${MUNGE_KEYDIR}"
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0103-munged-security-logfile.t b/t/0103-munged-security-logfile.t
index c9887fdd..fafd9735 100755
--- a/t/0103-munged-security-logfile.t
+++ b/t/0103-munged-security-logfile.t
@@ -358,4 +358,10 @@ test_expect_success 'logfile failure writes single message to stderr' '
     test "${NUM}" -eq 1 2>/dev/null
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0104-munged-security-pidfile.t b/t/0104-munged-security-pidfile.t
index dbe58252..0c2a505e 100755
--- a/t/0104-munged-security-pidfile.t
+++ b/t/0104-munged-security-pidfile.t
@@ -42,4 +42,10 @@ test_expect_failure 'finish writing tests' '
     false
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0105-munged-security-seedfile.t b/t/0105-munged-security-seedfile.t
index 31debc2c..5008239e 100755
--- a/t/0105-munged-security-seedfile.t
+++ b/t/0105-munged-security-seedfile.t
@@ -50,4 +50,10 @@ test_expect_failure 'finish writing tests' '
     false
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/0110-munged-origin-addr.t b/t/0110-munged-origin-addr.t
index 3b4d3690..7d0589c9 100755
--- a/t/0110-munged-origin-addr.t
+++ b/t/0110-munged-origin-addr.t
@@ -139,4 +139,10 @@ test_expect_success 'munged --origin non-interface IP address metadata' '
     egrep "^ENCODE_HOST:.* 192\.0\.0\.255\>" meta.$$
 '
 
+# Clean up after a munged process that may not have terminated.
+##
+test_expect_success 'cleanup' '
+    munged_cleanup
+'
+
 test_done
diff --git a/t/sharness.d/03-munged.sh b/t/sharness.d/03-munged.sh
index 0168326d..6f6e975a 100644
--- a/t/sharness.d/03-munged.sh
+++ b/t/sharness.d/03-munged.sh
@@ -73,19 +73,22 @@ munged_create_key()
 }
 
 ##
-# Start munged, removing an existing logfile (from a previous run) if present.
+# Start munged, removing an existing logfile or killing an errant munged
+#   process (from a previous run) if needed.
 # The following leading args are recognized:
 #   t-exec=ARG - use ARG to exec munged.
 #   t-keep-logfile - do not remove logfile before starting munged.
+#   t-keep-process - do not kill previous munged process.
 # Remaining args will be appended to the munged command-line.
 ##
 munged_start_daemon()
 {
-    local EXEC= KEEP_LOGFILE= &&
+    local EXEC= KEEP_LOGFILE= KEEP_PROCESS= &&
     while true; do
         case $1 in
             t-exec=*) EXEC=$(echo "$1" | sed 's/^[^=]*=//');;
             t-keep-logfile) KEEP_LOGFILE=1;;
+            t-keep-process) KEEP_PROCESS=1;;
             *) break;;
         esac
         shift
@@ -93,6 +96,9 @@ munged_start_daemon()
     if test "${KEEP_LOGFILE}" != 1; then
         rm -f "${MUNGE_LOGFILE}"
     fi &&
+    if test "${KEEP_PROCESS}" != 1; then
+        munged_kill_daemon
+    fi &&
     test_debug "echo ${EXEC} \"${MUNGED}\" \
             --socket=\"${MUNGE_SOCKET}\" \
             --key-file=\"${MUNGE_KEYFILE}\" \
@@ -136,3 +142,35 @@ munged_stop_daemon()
             --stop \
             "$@"
 }
+
+##
+# Kill an errant munged process running in the background from a previous test.
+# This situation is most likely to occur if a munged test is expected to fail
+#   and instead erroneously succeeds.
+# Only check for the pid named in ${MUNGE_PIDFILE} to avoid intefering with
+#   munged processes belonging to other tests or system use.  And check that
+#   the named pid is a munged process and not one recycled by the system for
+#   some other running process.
+# A SIGTERM is used here instead of "munged --stop" in case the latter has a
+#   bug introduced that prevents cleanup from occurring.
+# A SIGKILL would prevent the munged process from cleaning up which could cause
+#   other tests to inadvertently fail.
+##
+munged_kill_daemon()
+{
+    local PID
+    PID=$(cat "${MUNGE_PIDFILE}" 2>/dev/null)
+    if ps -p "${PID}" -ww 2>/dev/null | grep munged; then
+        kill "${PID}"
+        test_debug "echo \"Killed munged pid ${PID}\""
+    fi
+}
+
+##
+#  Perform any housekeeping to clean up after munged.  This should be called
+#    at the end of any test script that starts a munged process.
+##
+munged_cleanup()
+{
+    munged_kill_daemon
+}