diff --git a/changelog/15104.txt b/changelog/15104.txt
new file mode 100644
index 0000000000000..39ea1f577eb97
--- /dev/null
+++ b/changelog/15104.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+sdk: Fix OpenApi spec generator to properly convert TypeInt64 to OAS supported int64
+```
diff --git a/sdk/framework/openapi.go b/sdk/framework/openapi.go
index 02667cda4d237..847ad1065d0d8 100644
--- a/sdk/framework/openapi.go
+++ b/sdk/framework/openapi.go
@@ -556,6 +556,9 @@ func convertType(t FieldType) schemaType {
 		ret.format = "lowercase"
 	case TypeInt:
 		ret.baseType = "integer"
+	case TypeInt64:
+		ret.baseType = "integer"
+		ret.format = "int64"
 	case TypeDurationSecond, TypeSignedDurationSecond:
 		ret.baseType = "integer"
 		ret.format = "seconds"