diff --git a/tests/common/config_test.py b/tests/common/config_test.py
index 3ed9c797b7..a1c8a31d42 100644
--- a/tests/common/config_test.py
+++ b/tests/common/config_test.py
@@ -135,6 +135,16 @@ def test_multinode_vllm_requires_full_node_occupancy(self):
         with self.assertRaisesRegex(ValueError, "to be a multiple of"):
             config.check_and_update()
 
+    def test_sync_interval_overrides_must_be_positive(self):
+        for field in ("explorer_sync_interval", "trainer_sync_interval"):
+            with self.subTest(field=field):
+                config = get_template_config()
+                config.synchronizer.sync_interval = 4
+                setattr(config.synchronizer, field, 0)
+
+                with self.assertRaisesRegex(AssertionError, f"`{field}` must be positive"):
+                    config.check_and_update()
+
     def test_load_default_config(self):
         config = get_template_config()
         config.buffer.batch_size = 8
diff --git a/trinity/common/config_validator.py b/trinity/common/config_validator.py
index abc38b1332..551e17af38 100644
--- a/trinity/common/config_validator.py
+++ b/trinity/common/config_validator.py
@@ -868,6 +868,12 @@ def validate(self, config: Config) -> None:
             config.synchronizer, "explorer_sync_interval", config.synchronizer.sync_interval
         )
         set_if_none(config.synchronizer, "trainer_sync_interval", config.synchronizer.sync_interval)
+        assert (
+            config.synchronizer.explorer_sync_interval > 0
+        ), "`explorer_sync_interval` must be positive."
+        assert (
+            config.synchronizer.trainer_sync_interval > 0
+        ), "`trainer_sync_interval` must be positive."
 
 
 class IntervalConfigValidator(ConfigValidator):