diff --git a/Doc/extending/newtypes.rst b/Doc/extending/newtypes.rst
index 80a1387db20..56b40acdb69 100644
--- a/Doc/extending/newtypes.rst
+++ b/Doc/extending/newtypes.rst
@@ -337,7 +337,7 @@ Here is an example::
        }
 
        PyErr_Format(PyExc_AttributeError,
-                    "'%.50s' object has no attribute '%.400s'",
+                    "'%.100s' object has no attribute '%.400s'",
                     tp->tp_name, name);
        return NULL;
    }
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 9c12c696757..fd2fd9ab25f 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -946,7 +946,7 @@ local_setattro(localobject *self, PyObject *name, PyObject *v)
     }
     if (r == 1) {
         PyErr_Format(PyExc_AttributeError,
-                     "'%.50s' object attribute '%U' is read-only",
+                     "'%.100s' object attribute '%U' is read-only",
                      Py_TYPE(self)->tp_name, name);
         return -1;
     }
diff --git a/Objects/object.c b/Objects/object.c
index e508881c67d..a784e6bcbf9 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -1033,7 +1033,7 @@ PyObject_GetAttr(PyObject *v, PyObject *name)
     }
     else {
         PyErr_Format(PyExc_AttributeError,
-                    "'%.50s' object has no attribute '%U'",
+                    "'%.100s' object has no attribute '%U'",
                     tp->tp_name, name);
     }
 
@@ -1353,7 +1353,7 @@ _PyObject_GetMethod(PyObject *obj, PyObject *name, PyObject **method)
     }
 
     PyErr_Format(PyExc_AttributeError,
-                 "'%.50s' object has no attribute '%U'",
+                 "'%.100s' object has no attribute '%U'",
                  tp->tp_name, name);
 
     set_attribute_error_context(obj, name);
@@ -1474,7 +1474,7 @@ _PyObject_GenericGetAttrWithDict(PyObject *obj, PyObject *name,
 
     if (!suppress) {
         PyErr_Format(PyExc_AttributeError,
-                     "'%.50s' object has no attribute '%U'",
+                     "'%.100s' object has no attribute '%U'",
                      tp->tp_name, name);
 
         set_attribute_error_context(obj, name);
@@ -1545,7 +1545,7 @@ _PyObject_GenericSetAttrWithDict(PyObject *obj, PyObject *name,
             }
             else {
                 PyErr_Format(PyExc_AttributeError,
-                            "'%.50s' object attribute '%U' is read-only",
+                            "'%.100s' object attribute '%U' is read-only",
                             tp->tp_name, name);
             }
             goto done;
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 85bcd05d5a2..748965da0b4 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -4328,7 +4328,7 @@ _Py_type_getattro_impl(PyTypeObject *type, PyObject *name, int * suppress_missin
     /* Give up */
     if (suppress_missing_attribute == NULL) {
         PyErr_Format(PyExc_AttributeError,
-                        "type object '%.50s' has no attribute '%U'",
+                        "type object '%.100s' has no attribute '%U'",
                         type->tp_name, name);
     } else {
         // signal the caller we have not set an PyExc_AttributeError and gave up