diff --git a/src/external/tinyobj_loader_c.h b/src/external/tinyobj_loader_c.h
index 242b47d85..6bd63fceb 100644
--- a/src/external/tinyobj_loader_c.h
+++ b/src/external/tinyobj_loader_c.h
@@ -1377,7 +1377,7 @@ int tinyobj_parse_obj(tinyobj_attrib_t *attrib, tinyobj_shape_t **shapes,
           /* Create a null terminated string */
           char* material_name_null_term = (char*) TINYOBJ_MALLOC(commands[i].material_name_len + 1);
           memcpy((void*) material_name_null_term, (const void*) commands[i].material_name, commands[i].material_name_len);
-          material_name_null_term[commands[i].material_name_len - 1] = 0;
+          material_name_null_term[commands[i].material_name_len] = 0;
 
           if (hash_table_exists(material_name_null_term, &material_table))
             material_id = (int)hash_table_get(material_name_null_term, &material_table);