diff --git a/tools/importer-msgraph-metadata/components/parser/types.go b/tools/importer-msgraph-metadata/components/parser/types.go
index 20a7faff251..37546c06486 100644
--- a/tools/importer-msgraph-metadata/components/parser/types.go
+++ b/tools/importer-msgraph-metadata/components/parser/types.go
@@ -737,7 +737,7 @@ func Schemas(input flattenedSchema, name string, models Models, constants Consta
 		}
 
 		// Detect nullable, read-only and requried fields from the description
-		if strings.Contains(schema.Description, "Nullable.") {
+		if strings.Contains(schema.Description, "Nullable.") && !strings.Contains(strings.ToLower(schema.Description), "not nullable.") {
 			field.Nullable = true
 		}
 		if strings.Contains(schema.Description, "Read-only.") {