diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index 46b15234a19c63c..4c28957a9d8b154 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -56,6 +56,9 @@ bpo-26353: Stop adding newline when saving an IDLE shell window.
 
 bpo-38598: Do not try to compile IDLE shell or output windows.
 
+bpo-23937: Add option to maximise IDLE windows on load
+(applies for both shell and editor windows).
+
 
 What's New in IDLE 3.8.0 (since 3.7.0)
 Released on 2019-10-14
diff --git a/Lib/idlelib/config-main.def b/Lib/idlelib/config-main.def
index 28ae94161d5c035..fee59212891c835 100644
--- a/Lib/idlelib/config-main.def
+++ b/Lib/idlelib/config-main.def
@@ -57,6 +57,7 @@ print-command-win=start /min notepad /p %%s
 delete-exitfunc= 1
 
 [EditorWindow]
+max= 0
 width= 80
 height= 40
 cursor-blink= 1
diff --git a/Lib/idlelib/configdialog.py b/Lib/idlelib/configdialog.py
index 82596498d346111..d7ecb5a80e5c665 100644
--- a/Lib/idlelib/configdialog.py
+++ b/Lib/idlelib/configdialog.py
@@ -1817,6 +1817,7 @@ def create_page_general(self):
                     (*)startup_shell_on: Radiobutton - startup_edit
                 frame_win_size: Frame
                     win_size_title: Label
+                    (*)win_max_title: Checkbutton - win_max
                     win_width_title: Label
                     (*)win_width_int: Entry - win_width
                     win_height_title: Label
@@ -1864,6 +1865,8 @@ def create_page_general(self):
         # Integer values need StringVar because int('') raises.
         self.startup_edit = tracers.add(
                 IntVar(self), ('main', 'General', 'editor-on-startup'))
+        self.win_max = tracers.add(
+                BooleanVar(self), ('main', 'EditorWindow', 'max'))
         self.win_width = tracers.add(
                 StringVar(self), ('main', 'EditorWindow', 'width'))
         self.win_height = tracers.add(
@@ -1915,6 +1918,8 @@ def create_page_general(self):
         frame_win_size = Frame(frame_window, borderwidth=0)
         win_size_title = Label(
                 frame_win_size, text='Initial Window Size  (in characters)')
+        win_max_title = Checkbutton(frame_win_size, text='Maximised', variable=self.win_max)
+        self.win_max.trace("w", lambda a, b, c: self.toggle_entry_mode())
         win_width_title = Label(frame_win_size, text='Width')
         self.win_width_int = Entry(
                 frame_win_size, textvariable=self.win_width, width=3,
@@ -2030,7 +2035,8 @@ def create_page_general(self):
         self.startup_editor_on.pack(side=RIGHT, anchor=W, padx=5, pady=5)
         # frame_win_size.
         frame_win_size.pack(side=TOP, padx=5, pady=0, fill=X)
-        win_size_title.pack(side=LEFT, anchor=W, padx=5, pady=5)
+        win_size_title.pack(side=LEFT, anchor=NW, padx=5, pady=5)
+        win_max_title.pack(side=TOP, anchor=E, padx=10, pady=5)
         self.win_height_int.pack(side=RIGHT, anchor=E, padx=10, pady=5)
         win_height_title.pack(side=RIGHT, anchor=E, pady=5)
         self.win_width_int.pack(side=RIGHT, anchor=E, padx=10, pady=5)
@@ -2089,6 +2095,8 @@ def load_general_cfg(self):
         # Set variables for all windows.
         self.startup_edit.set(idleConf.GetOption(
                 'main', 'General', 'editor-on-startup', type='bool'))
+        self.win_max.set(idleConf.GetOption(
+                'main', 'EditorWindow', 'max', type='bool'))
         self.win_width.set(idleConf.GetOption(
                 'main', 'EditorWindow', 'width', type='int'))
         self.win_height.set(idleConf.GetOption(
@@ -2125,6 +2133,14 @@ def load_general_cfg(self):
             self.helplist.insert(END, help_item[0])
         self.set_add_delete_state()
 
+    def toggle_entry_mode(self):
+        if self.win_max.get():
+            state = "disabled"
+        else:
+            state = "normal"
+        self.win_width_int.config(state=state)
+        self.win_height_int.config(state=state)
+
     def help_source_selected(self, event):
         "Handle event for selecting additional help."
         self.set_add_delete_state()
diff --git a/Lib/idlelib/editor.py b/Lib/idlelib/editor.py
index b0f88b5463d1b6e..7d98ef70a1a5dd2 100644
--- a/Lib/idlelib/editor.py
+++ b/Lib/idlelib/editor.py
@@ -107,6 +107,11 @@ def __init__(self, flist=None, filename=None, key=None, root=None):
         self.root = root
         self.menubar = Menu(root)
         self.top = top = window.ListedToplevel(root, menu=self.menubar)
+        if idleConf.GetOption('main', 'EditorWindow', 'max', type='bool'):
+            if sys.platform[:3] == 'win':
+                self.top.state('zoomed')
+            else:
+                self.top.attributes('-zoomed', True)
         if flist:
             self.tkinter_vars = flist.vars
             #self.top.instance_dict makes flist.inversedict available to