diff --git a/opentelemetry-semantic-conventions/src/opentelemetry/semconv/schemas.py b/opentelemetry-semantic-conventions/src/opentelemetry/semconv/schemas.py
index 59d25ae6b05..6258f869547 100644
--- a/opentelemetry-semantic-conventions/src/opentelemetry/semconv/schemas.py
+++ b/opentelemetry-semantic-conventions/src/opentelemetry/semconv/schemas.py
@@ -16,6 +16,11 @@
 
 
 class Schemas(Enum):
+    V1_21_0 = "https://opentelemetry.io/schemas/1.21.0"
+    """
+    The URL of the OpenTelemetry schema version 1.21.0.
+    """
+
     V1_23_1 = "https://opentelemetry.io/schemas/1.23.1"
     """
     The URL of the OpenTelemetry schema version 1.23.1.