diff --git a/src/sentry/api/endpoints/organization_traces.py b/src/sentry/api/endpoints/organization_traces.py
index d04ad8ae31d3ec..b1f3fded4cbf2b 100644
--- a/src/sentry/api/endpoints/organization_traces.py
+++ b/src/sentry/api/endpoints/organization_traces.py
@@ -28,7 +28,7 @@
     SpansIndexedQueryBuilder,
     TimeseriesSpanIndexedQueryBuilder,
 )
-from sentry.search.events.constants import TIMEOUT_SPAN_ERROR_MESSAGE
+from sentry.search.events.constants import TIMEOUT_SPAN_ERROR_MESSAGE, UNCLASSIFIED_SPAN_GROUP
 from sentry.search.events.types import ParamsType, QueryBuilderConfig, SnubaParams, WhereType
 from sentry.sentry_metrics.querying.samples_list import SpanKey, get_sample_list_executor_cls
 from sentry.services.hybrid_cloud.organization import RpcOrganization
@@ -854,11 +854,18 @@ def get_traces_breakdown_projects_query(
     ) -> QueryBuilder:
         trace_ids_str = ",".join(trace_ids)
         trace_ids_condition = f"trace:[{trace_ids_str}]"
+        query = " ".join(
+            [
+                "is_transaction:1",  # service entry spans
+                f"group:{UNCLASSIFIED_SPAN_GROUP}",  # service entry spans do not have a group
+                trace_ids_condition,
+            ],
+        )
         return SpansIndexedQueryBuilder(
             Dataset.SpansIndexed,
             params,
             snuba_params=snuba_params,
-            query=f"is_transaction:1 {trace_ids_condition}",
+            query=query,
             selected_columns=[
                 "trace",
                 "project",
diff --git a/src/sentry/search/events/constants.py b/src/sentry/search/events/constants.py
index 9dd490b5291cc9..47c04f803f987f 100644
--- a/src/sentry/search/events/constants.py
+++ b/src/sentry/search/events/constants.py
@@ -56,6 +56,9 @@
 SPAN_DESCRIPTION = "span.description"
 SPAN_STATUS = "span.status"
 
+# Not all spans get a group assigned to it. Unassigned ones has a default of 0.
+UNCLASSIFIED_SPAN_GROUP = "00"
+
 
 class ThresholdDict(TypedDict):
     poor: float
diff --git a/src/sentry/sentry_metrics/querying/samples_list.py b/src/sentry/sentry_metrics/querying/samples_list.py
index bb3d229564c9b1..5307a39b6978b3 100644
--- a/src/sentry/sentry_metrics/querying/samples_list.py
+++ b/src/sentry/sentry_metrics/querying/samples_list.py
@@ -14,6 +14,7 @@
     QueryBuilder,
     SpansIndexedQueryBuilder,
 )
+from sentry.search.events.constants import UNCLASSIFIED_SPAN_GROUP
 from sentry.search.events.types import ParamsType, QueryBuilderConfig, SelectType, SnubaParams
 from sentry.snuba.dataset import Dataset
 from sentry.snuba.metrics.naming_layer.mri import (
@@ -277,7 +278,7 @@ def get_matching_spans_from_traces(
 
         return [
             SpanKey(
-                group="00",  # all segments have a group of `00` currently
+                group=UNCLASSIFIED_SPAN_GROUP,
                 timestamp=row["timestamp"],
                 span_id=row["span_id"],
             )