diff --git a/t/sharness.d/flux-sharness.sh b/t/sharness.d/flux-sharness.sh
index 0de82a43460c..3f16388cb745 100644
--- a/t/sharness.d/flux-sharness.sh
+++ b/t/sharness.d/flux-sharness.sh
@@ -24,6 +24,37 @@ test_size_large() {
     echo ${size}
 }
 
+
+#
+#  Tests using test_under_flux() and which load their own modules should
+#   ensure those modules are unloaded at the end of the test for proper
+#   cleanup and test coverage (also as a general principle, module unload
+#   should be something explicitly tested).
+#
+#  The functions below ensure that every module loaded at "test_done" time
+#   when test_under_flux() was used was also loaded before test_under_flux
+#   was called.
+#
+flux_module_list() {
+    flux module list | awk '!/^Module/{print $1}' | sort
+}
+
+check_module_list() {
+    flux_module_list > module-list.final
+    while read module; do
+       grep "^$module$" module-list.initial >/dev/null 2>&1 \
+            || bad="${bad}${bad:+ }$module"
+    done < module-list.final
+    if test -n "$bad"; then
+        test -n "$logfile" \
+            && say_color error >&3 \
+                 "Error: manually loaded module(s) not unloaded: $bad"
+        # This function is run under test_eval_ so redirect
+        #  error message to &5 (saved stdout) so text doesn't disappear:
+        error >&5 2>&1 "manually loaded module(s) not unloaded: $bad"
+    fi
+}
+
 #
 #  Reinvoke a test file under a flux comms instance
 #
@@ -35,6 +66,8 @@ test_under_flux() {
     log_file="$TEST_NAME.broker.log"
     if test -n "$TEST_UNDER_FLUX_ACTIVE" ; then
         cleanup rm "${SHARNESS_TEST_DIRECTORY:-..}/$log_file"
+        flux_module_list > module-list.initial
+        cleanup check_module_list
         return
     fi
     quiet="-o -q,-Slog-filename=${log_file},-Slog-forward-level=7"
diff --git a/t/t0001-basic.t b/t/t0001-basic.t
index 9e52f948c9e4..c9ef42d74695 100755
--- a/t/t0001-basic.t
+++ b/t/t0001-basic.t
@@ -120,6 +120,35 @@ test_expect_success 'test_under_flux works' '
 	) &&
 	grep "size=2" test-under-flux/out
 '
+
+test_expect_success 'test_under_flux fails if loaded modules are not unloaded' '
+    mkdir -p test-under-flux && (
+		cd test-under-flux &&
+		cat >.test.modcheck.t <<-EOF &&
+		#!/bin/sh
+		test_description="test_under_flux with module loaded, but not unloaded"
+		. "\$SHARNESS_TEST_SRCDIR"/sharness.sh
+		test_under_flux 2 minimal
+		test_expect_success "flux module load kvs" "
+			flux module load -r 0 kvs
+		"
+		test_done
+		EOF
+		chmod +x .test.modcheck.t &&
+		SHARNESS_TEST_DIRECTORY=`pwd` &&
+		export SHARNESS_TEST_SRCDIR SHARNESS_TEST_DIRECTORY FLUX_BUILD_DIR debug &&
+		test_expect_code 1 ./.test.modcheck.t 2>err.modcheck \
+			| grep -v sharness: >out.modcheck
+	) &&
+	cat >expected.modcheck <<-EOF &&
+	ok 1 - flux module load kvs
+	# passed all 1 test(s)
+	1..1
+	error: manually loaded module(s) not unloaded: kvs
+	EOF
+	test_cmp expected.modcheck test-under-flux/out.modcheck
+'
+
 test_expect_success 'flux-start -o,--setattr ATTR=VAL can set broker attributes' '
 	ATTR_VAL=`flux start ${ARGS} -o,--setattr=foo-test=42 flux getattr foo-test` &&
 	test $ATTR_VAL -eq 42