diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-04-10-22-16-18.gh-issue-117709.-_1YL0.rst b/Misc/NEWS.d/next/Core and Builtins/2024-04-10-22-16-18.gh-issue-117709.-_1YL0.rst
new file mode 100644
index 00000000000000..1877ac5818cb69
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2024-04-10-22-16-18.gh-issue-117709.-_1YL0.rst	
@@ -0,0 +1,2 @@
+Speed up calls to :func:`str` by using the :pep:`590` ``vectorcall`` calling
+convention. Patch by Erlend Aasland.
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 5f15071d7d54ef..2a6f05d59baecd 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -14617,6 +14617,115 @@ unicode_new_impl(PyTypeObject *type, PyObject *x, const char *encoding,
     return unicode;
 }
 
+static const char *
+as_const_char(PyObject *obj, const char *name)
+{
+    if (!PyUnicode_Check(obj)) {
+        PyErr_Format(PyExc_TypeError,
+                     "str() argument '%s' must be str, not %T",
+                     name, obj);
+        return NULL;
+    }
+    const char *str = _PyUnicode_AsUTF8NoNUL(obj);
+    if (str == NULL) {
+        return NULL;
+    }
+    return str;
+}
+
+static PyObject *
+fallback_to_tp_call(PyObject *type, Py_ssize_t nargs, Py_ssize_t nkwargs,
+                    PyObject *const *args, PyObject *kwnames)
+{
+    PyObject *tuple = _PyTuple_FromArray(args, nargs);
+    if (tuple == NULL) {
+        return NULL;
+    }
+    PyObject *dict = _PyStack_AsDict(args + nargs, kwnames);
+    if (dict == NULL) {
+        Py_DECREF(tuple);
+        return NULL;
+    }
+    return unicode_new(_PyType_CAST(type), tuple, dict);
+}
+
+static PyObject *
+unicode_vectorcall(PyObject *type, PyObject *const *args,
+                   size_t nargsf, PyObject *kwnames)
+{
+    assert(Py_Is(_PyType_CAST(type), &PyUnicode_Type));
+
+    Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
+    Py_ssize_t nkwargs = (kwnames) ? PyTuple_GET_SIZE(kwnames) : 0;
+    if (nargs == 0 && nkwargs == 0) {
+        return unicode_get_empty();
+    }
+    PyObject *object = args[0];
+    if (nargs == 1 && nkwargs == 0) {
+        return PyObject_Str(object);
+    }
+    if (nargs + nkwargs == 2) {
+        const char *encoding = NULL;
+        const char *errors = NULL;
+        if (nkwargs == 1) {
+            PyObject *key = PyTuple_GET_ITEM(kwnames, 0);
+            if (_PyUnicode_EqualToASCIIString(key, "encoding")) {
+                encoding = as_const_char(args[1], "encoding");
+                if (encoding == NULL) {
+                    return NULL;
+                }
+            }
+            else if (_PyUnicode_EqualToASCIIString(key, "errors")) {
+                errors = as_const_char(args[1], "errors");
+                if (errors == NULL) {
+                    return NULL;
+                }
+            }
+            else {
+                PyErr_Format(PyExc_TypeError,
+                    "str() got an unexpected keyword argument %R", key);
+                return NULL;
+            }
+        }
+        else if (nkwargs == 0) {
+            encoding = as_const_char(args[1], "encoding");
+        }
+        else {
+            return fallback_to_tp_call(type, nargs, nkwargs, args, kwnames);
+        }
+        return PyUnicode_FromEncodedObject(object, encoding, errors);
+    }
+    if (nargs + nkwargs == 3) {
+        if (nkwargs == 1) {
+            PyObject *key = PyTuple_GET_ITEM(kwnames, 0);
+            if (!_PyUnicode_EqualToASCIIString(key, "errors")) {
+                PyErr_Format(PyExc_TypeError,
+                    "str() got an unexpected keyword argument %R", key);
+                return NULL;
+            }
+        }
+        else if (nkwargs != 0) {
+            return fallback_to_tp_call(type, nargs, nkwargs, args, kwnames);
+        }
+        const char *encoding = as_const_char(args[1], "encoding");
+        if (encoding == NULL) {
+            return NULL;
+        }
+        const char *errors = as_const_char(args[2], "errors");
+        if (errors == NULL) {
+            return NULL;
+        }
+        return PyUnicode_FromEncodedObject(object, encoding, errors);
+    }
+    if (nargs > 3) {
+        PyErr_Format(PyExc_TypeError,
+            "str() takes at most 3 arguments (%d given)", nargs + nkwargs);
+        return NULL;
+    }
+
+    return fallback_to_tp_call(type, nargs, nkwargs, args, kwnames);
+}
+
 static PyObject *
 unicode_subtype_new(PyTypeObject *type, PyObject *unicode)
 {
@@ -14758,6 +14867,7 @@ PyTypeObject PyUnicode_Type = {
     0,                            /* tp_alloc */
     unicode_new,                  /* tp_new */
     PyObject_Del,                 /* tp_free */
+    .tp_vectorcall = unicode_vectorcall,
 };
 
 /* Initialize the Unicode implementation */