diff -r 34881ee3eec5 Lib/idlelib/AutoComplete.py
--- a/Lib/idlelib/AutoComplete.py	Mon Jun 16 11:14:47 2014 -0500
+++ b/Lib/idlelib/AutoComplete.py	Thu Jun 19 21:08:16 2014 -0300
@@ -13,7 +13,7 @@
 ID_CHARS = string.ascii_letters + string.digits + "_"
 
 # These constants represent the two different types of completions
-COMPLETE_ATTRIBUTES, COMPLETE_FILES = range(1, 2+1)
+COMPLETE_ATTRIBUTES, COMPLETE_FILES, COMPLETE_DICTIONARY = range(1, 3+1)
 
 from idlelib import AutoCompleteWindow
 from idlelib.HyperParser import HyperParser
@@ -120,7 +120,18 @@
         hp = HyperParser(self.editwin, "insert")
         curline = self.text.get("insert linestart", "insert")
         i = j = len(curline)
-        if hp.is_in_string() and (not mode or mode==COMPLETE_FILES):
+        if hp.is_in_subscript_string() and (not mode or mode==COMPLETE_DICTIONARY):
+            self._remove_autocomplete_window()
+            mode = COMPLETE_DICTIONARY
+            while i and (curline[i-1] not in "'"):
+                i -= 1
+            comp_start = curline[i:j]
+            if i > 1 and curline[i-2] == '[':
+                hp.set_index("insert-%dc" % (len(curline)-(i-2)))
+                comp_what = hp.get_expression()
+            else:
+                comp_what = ""
+        elif hp.is_in_string() and (not mode or mode==COMPLETE_FILES):
             # Find the beginning of the string
             # fetch_completions will look at the file system to determine whether the
             # string value constitutes an actual file name
@@ -184,6 +195,7 @@
             return rpcclt.remotecall("exec", "get_the_completion_list",
                                      (what, mode), {})
         else:
+            smalll = bigl = None
             if mode == COMPLETE_ATTRIBUTES:
                 if what == "":
                     namespace = __main__.__dict__.copy()
@@ -217,6 +229,14 @@
                 except OSError:
                     return [], []
 
+            elif mode == COMPLETE_DICTIONARY:
+                try:
+                    entity = self.get_entity(what)
+                    bigl = [s for s in entity.keys() if isinstance(s,str)]
+                    bigl.sort()
+                except:
+                    return [], []
+
             if not smalll:
                 smalll = bigl
             return smalll, bigl
diff -r 34881ee3eec5 Lib/idlelib/HyperParser.py
--- a/Lib/idlelib/HyperParser.py	Mon Jun 16 11:14:47 2014 -0500
+++ b/Lib/idlelib/HyperParser.py	Thu Jun 19 21:08:16 2014 -0300
@@ -87,6 +87,15 @@
            not self.isopener[self.indexbracket+1]):
             self.indexbracket += 1
 
+    def is_in_subscript_string(self):
+        """Is the index given to the HyperParser in a string inside
+        a subscript?
+        """
+        return (self.indexbracket and
+                self.is_in_string() and
+                self.isopener[self.indexbracket-1] and
+                self.rawtext[self.bracketing[self.indexbracket-1][0]] == '[')
+
     def is_in_string(self):
         """Is the index given to the HyperParser is in a string?"""
         # The bracket to which we belong should be an opener.