diff --git a/kitty/child-monitor.c b/kitty/child-monitor.c
index dfd070261..612c9f8cd 100644
--- a/kitty/child-monitor.c
+++ b/kitty/child-monitor.c
@@ -14,6 +14,7 @@
 #undef _GNU_SOURCE
 #endif
 #include "data-types.h"
+#include <termios.h>
 #include <unistd.h>
 #include <float.h>
 #include <fcntl.h>
@@ -356,6 +357,38 @@ resize_pty(ChildMonitor *self, PyObject *args) {
     return found;
 }
 
+bool
+set_iutf8(int UNUSED fd, bool UNUSED on) {
+#ifdef IUTF8
+    struct termios attrs;
+    if (tcgetattr(fd, &attrs) != 0) return false;
+    if (on) attrs.c_iflag |= IUTF8;
+    else attrs.c_iflag &= ~IUTF8;
+    if (tcsetattr(fd, TCSANOW, &attrs) != 0) return false;
+#endif
+    return true;
+}
+
+static PyObject*
+pyset_iutf8(ChildMonitor *self, PyObject *args) {
+    unsigned long window_id;
+    int on;
+    PyObject *found = Py_False;
+    if (!PyArg_ParseTuple(args, "kp", &window_id, &on)) return NULL;
+    children_mutex(lock);
+    for (size_t i = 0; i < self->count; i++) {
+        if (children[i].id == window_id) {
+            found = Py_True;
+            if (!set_iutf8(fds[EXTRA_FDS + i].fd, on & 1)) PyErr_SetFromErrno(PyExc_OSError);
+            break;
+        }
+    }
+    children_mutex(unlock);
+    if (PyErr_Occurred()) return NULL;
+    Py_INCREF(found);
+    return found;
+}
+
 #undef FREE_CHILD
 #undef INCREF_CHILD
 #undef DECREF_CHILD
@@ -581,6 +614,7 @@ static PyMethodDef methods[] = {
     METHOD(main_loop, METH_NOARGS)
     METHOD(mark_for_close, METH_VARARGS)
     METHOD(resize_pty, METH_VARARGS)
+    {"set_iutf8", (PyCFunction)pyset_iutf8, METH_VARARGS, ""},
     {NULL}  /* Sentinel */
 };
 
diff --git a/kitty/child.py b/kitty/child.py
index bf1c16d83..76a2973c0 100644
--- a/kitty/child.py
+++ b/kitty/child.py
@@ -3,7 +3,6 @@
 # License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
 import os
-import termios
 import fcntl
 import signal
 from threading import Thread
@@ -33,7 +32,7 @@ class Child:
         self.forked = True
         master, slave = os.openpty()  # Note that master and slave are in blocking mode
         remove_cloexec(slave)
-        self.set_iutf8(fd=master)
+        fast_data_types.set_iutf8(master, True)
         stdin, self.stdin = self.stdin, None
         if stdin is not None:
             stdin_read_fd, stdin_write_fd = os.pipe()
@@ -76,16 +75,6 @@ class Child:
                 t.start()
             return pid
 
-    def set_iutf8(self, on=True, fd=None):
-        fd = fd or self.child_fd
-        if fd is not None and hasattr(fast_data_types, 'IUTF8'):
-            attrs = termios.tcgetattr(fd)
-            if on:
-                attrs[0] |= fast_data_types.IUTF8
-            else:
-                attrs[0] &= ~fast_data_types.IUTF8
-            termios.tcsetattr(fd, termios.TCSANOW, attrs)
-
     def hangup(self):
         if self.pid is not None:
             pid, self.pid = self.pid, None
diff --git a/kitty/data-types.c b/kitty/data-types.c
index 37f301dd4..e3c946bb2 100644
--- a/kitty/data-types.c
+++ b/kitty/data-types.c
@@ -37,6 +37,14 @@ redirect_std_streams(PyObject UNUSED *self, PyObject *args) {
     Py_RETURN_NONE;
 }
 
+static PyObject*
+pyset_iutf8(PyObject UNUSED *self, PyObject *args) {
+    int fd, on;
+    if (!PyArg_ParseTuple(args, "ip", &fd, &on)) return NULL;
+    if (!set_iutf8(fd, on & 1)) return PyErr_SetFromErrno(PyExc_OSError);
+    Py_RETURN_NONE;
+}
+
 #ifdef WITH_PROFILER
 static PyObject*
 start_profiler(PyObject UNUSED *self, PyObject *args) {
@@ -59,6 +67,7 @@ stop_profiler(PyObject UNUSED *self) {
 
 static PyMethodDef module_methods[] = {
     GL_METHODS
+    {"set_iutf8", (PyCFunction)pyset_iutf8, METH_VARARGS, ""},
     {"parse_bytes", (PyCFunction)parse_bytes, METH_VARARGS, ""},
     {"parse_bytes_dump", (PyCFunction)parse_bytes_dump, METH_VARARGS, ""},
     {"redirect_std_streams", (PyCFunction)redirect_std_streams, METH_VARARGS, ""},
@@ -144,9 +153,6 @@ PyInit_fast_data_types(void) {
         PyModule_AddIntMacro(m, NORMAL_PROTOCOL);
         PyModule_AddIntMacro(m, URXVT_PROTOCOL);
         PyModule_AddIntMacro(m, UTF8_PROTOCOL);
-#ifdef IUTF8
-        PyModule_AddIntMacro(m, IUTF8);
-#endif
     }
 
     return m;
diff --git a/kitty/data-types.h b/kitty/data-types.h
index 626644912..f47720cef 100644
--- a/kitty/data-types.h
+++ b/kitty/data-types.h
@@ -355,6 +355,7 @@ double timers_timeout(Timers*);
 void timers_call(Timers*);
 bool timers_add(Timers *self, double delay, bool, PyObject *callback, PyObject *args);
 bool timers_add_if_missing(Timers *self, double delay, PyObject *callback, PyObject *args);
+bool set_iutf8(int, bool);
 
 color_type colorprofile_to_color(ColorProfile *self, color_type entry, color_type defval);
 
diff --git a/kitty/window.py b/kitty/window.py
index 664db4eaf..e72bb5def 100644
--- a/kitty/window.py
+++ b/kitty/window.py
@@ -130,7 +130,7 @@ class Window:
         glfw_post_empty_event()
 
     def use_utf8(self, on):
-        self.child.set_iutf8(on)
+        get_boss().child_monitor.set_iutf8(self.window_id, on)
 
     def update_screen(self):
         self.char_grid.update_cell_data()