diff --git a/st2common/tests/unit/test_db.py b/st2common/tests/unit/test_db.py
index 7fe10ef3f4..0ae1ee79f1 100644
--- a/st2common/tests/unit/test_db.py
+++ b/st2common/tests/unit/test_db.py
@@ -126,6 +126,7 @@ def test_check_connect(self):
     def test_network_level_compression(self):
         disconnect()
 
+        # db is not modified in this test, so this is safe to run in parallel.
         db_name = "st2"
         db_host = "localhost"
         db_port = 27017
@@ -521,6 +522,7 @@ def test_db_connect_server_selection_timeout_ssl_on_non_ssl_listener(self):
         # and propagating the error
         disconnect()
 
+        # db is not modified in this test, so this is safe to run in parallel.
         db_name = "st2"
         db_host = "localhost"
         db_port = 27017
diff --git a/st2tests/st2tests/config.py b/st2tests/st2tests/config.py
index feef6f589f..9848ffb626 100644
--- a/st2tests/st2tests/config.py
+++ b/st2tests/st2tests/config.py
@@ -85,7 +85,9 @@ def _register_config_opts():
 
 
 def _override_db_opts():
-    CONF.set_override(name="db_name", override="st2-test", group="database")
+    # use separate dbs for safer parallel test runs
+    db_name = f"st2-test{os.environ.get('ST2TESTS_PARALLEL_SLOT', '')}"
+    CONF.set_override(name="db_name", override=db_name, group="database")
     CONF.set_override(name="host", override="127.0.0.1", group="database")