diff --git a/tests/rules/test_quoted_strings.py b/tests/rules/test_quoted_strings.py
index 040ea793..f58cb13d 100644
--- a/tests/rules/test_quoted_strings.py
+++ b/tests/rules/test_quoted_strings.py
@@ -18,7 +18,7 @@
 from yamllint import config
 
 
-class QuotedTestCase(RuleTestCase):
+class QuotedValuesTestCase(RuleTestCase):
     rule_id = 'quoted-strings'
 
     def test_disabled(self):
@@ -595,3 +595,338 @@ def test_allow_quoted_quotes(self):
                    "foo1: '[barbaz]'\n"
                    "foo2: '[bar\"baz]'\n",
                    conf)
+
+
+class QuotedKeysTestCase(RuleTestCase):
+    rule_id = 'quoted-strings'
+
+    def conf(self, options):
+        conf_with_options = (f"{self.rule_id}:\n"
+                             "  check-keys: true\n")
+        for option in options:
+            conf_with_options += f"  {option}\n"
+        return conf_with_options
+
+    key_strings = ('---\n'
+                   'true: 2\n'
+                   '123: 3\n'
+                   'foo1: 4\n'
+                   '"foo2": 5\n'
+                   '"false": 6\n'
+                   '"234": 7\n'
+                   '\'bar\': 8\n'
+                   '!!str generic_string: 9\n'
+                   '!!str 456: 10\n'
+                   '!!str "quoted_generic_string": 11\n'
+                   '!!binary binstring: 12\n'
+                   '!!int int_string: 13\n'
+                   '!!bool bool_string: 14\n'
+                   '!!bool "quoted_bool_string": 15\n'
+                   # Sequences and mappings
+                   '? - 16\n'
+                   '  - 17\n'
+                   ': 18\n'
+                   '[119, 219]: 19\n'
+                   '? a: 20\n'
+                   '  "b": 21\n'
+                   ': 22\n'
+                   '{a: 123, "b": 223}: 23\n'
+                   # Multiline strings
+                   '? |\n'
+                   '  line 1\n'
+                   '  line 2\n'
+                   ': 27\n'
+                   '? >\n'
+                   '  line 1\n'
+                   '  line 2\n'
+                   ': 31\n'
+                   '?\n'
+                   '  line 1\n'
+                   '  line 2\n'
+                   ': 35\n'
+                   '?\n'
+                   '  "line 1\\\n'
+                   '   line 2"\n'
+                   ': 39\n')
+
+    def test_disabled(self):
+        conf_disabled = f"{self.rule_id}: {{}}"
+        self.check(self.key_strings, conf_disabled)
+
+    def test_default(self):
+        # Default configuration, but with check-keys
+        conf_default = (f"{self.rule_id}:\n"
+                        "  check-keys: true\n")
+        self.check(self.key_strings, conf_default, problem1=(4, 1),
+                   problem3=(20, 3), problem4=(23, 2), problem5=(33, 3))
+
+    def test_quote_type_any(self):
+        conf = self.conf(['quote-type: any'])
+
+        self.check(self.key_strings, conf,
+                   problem1=(4, 1), problem2=(20, 3), problem3=(23, 2),
+                   problem4=(33, 3))
+
+    def test_quote_type_single(self):
+        conf = self.conf(['quote-type: single'])
+
+        self.check(self.key_strings, conf,
+                   problem1=(4, 1), problem2=(5, 1), problem3=(6, 1),
+                   problem4=(7, 1), problem5=(20, 3), problem6=(21, 3),
+                   problem7=(23, 2), problem8=(23, 10), problem9=(33, 3),
+                   problem10=(37, 3))
+
+    def test_quote_type_double(self):
+        conf = self.conf(['quote-type: double'])
+
+        self.check(self.key_strings, conf,
+                   problem1=(4, 1), problem2=(8, 1), problem3=(20, 3),
+                   problem4=(23, 2), problem5=(33, 3))
+
+    def test_any_quotes_not_required(self):
+        conf = self.conf(['quote-type: any', 'required: false'])
+
+        self.check(self.key_strings, conf)
+
+    def test_single_quotes_not_required(self):
+        conf = self.conf(['quote-type: single', 'required: false'])
+
+        self.check(self.key_strings, conf,
+                   problem1=(5, 1), problem2=(6, 1), problem3=(7, 1),
+                   problem4=(21, 3), problem5=(23, 10), problem6=(37, 3))
+
+    def test_only_when_needed(self):
+        conf = self.conf(['required: only-when-needed'])
+
+        self.check(self.key_strings, conf,
+                   problem1=(5, 1), problem2=(8, 1), problem3=(21, 3),
+                   problem4=(23, 10), problem5=(37, 3))
+
+    def test_only_when_needed_single_quotes(self):
+        conf = self.conf(['quote-type: single', 'required: only-when-needed'])
+
+        self.check(self.key_strings, conf,
+                   problem1=(5, 1), problem2=(6, 1), problem3=(7, 1),
+                   problem4=(8, 1), problem5=(21, 3), problem6=(23, 10),
+                   problem7=(37, 3))
+
+    def test_only_when_needed_corner_cases(self):
+        conf = self.conf(['required: only-when-needed'])
+
+        self.check('---\n'
+                   '"": 2\n'
+                   '"- item": 3\n'
+                   '"key: value": 4\n'
+                   '"%H:%M:%S": 5\n'
+                   '"%wheel ALL=(ALL) NOPASSWD: ALL": 6\n'
+                   '\'"quoted"\': 7\n'
+                   '"\'foo\' == \'bar\'": 8\n'
+                   '"\'Mac\' in ansible_facts.product_name": 9\n'
+                   '\'foo # bar\': 10\n',
+                   conf)
+        self.check('---\n'
+                   '"": 2\n'
+                   '"- item": 3\n'
+                   '"key: value": 4\n'
+                   '"%H:%M:%S": 5\n'
+                   '"%wheel ALL=(ALL) NOPASSWD: ALL": 6\n'
+                   '\'"quoted"\': 7\n'
+                   '"\'foo\' == \'bar\'": 8\n'
+                   '"\'Mac\' in ansible_facts.product_name": 9\n',
+                   conf)
+
+        self.check('---\n'
+                   '---: 2\n'
+                   '"----": 3\n'                 # fails
+                   '---------: 4\n'
+                   '"----------": 5\n'           # fails
+                   ':wq: 6\n'
+                   '":cw": 7\n',                 # fails
+                   conf, problem1=(3, 1), problem2=(5, 1), problem3=(7, 1))
+
+    def test_only_when_needed_extras(self):
+        conf = self.conf(['required: true', 'extra-allowed: [^http://]'])
+        self.assertRaises(config.YamlLintConfigError, self.check, '', conf)
+
+        conf = self.conf(['required: true', 'extra-required: [^http://]'])
+        self.assertRaises(config.YamlLintConfigError, self.check, '', conf)
+
+        conf = self.conf(['required: false', 'extra-allowed: [^http://]'])
+        self.assertRaises(config.YamlLintConfigError, self.check, '', conf)
+
+        conf = self.conf(['required: true'])
+        self.check('---\n'
+                   '123: 2\n'
+                   '"234": 3\n'
+                   'localhost: 4\n'              # fails
+                   '"host.local": 5\n'
+                   'http://localhost: 6\n'       # fails
+                   '"http://host.local": 7\n'
+                   'ftp://localhost: 8\n'        # fails
+                   '"ftp://host.local": 9\n',
+                   conf, problem1=(4, 1), problem2=(6, 1), problem3=(8, 1))
+
+        conf = self.conf(['required: only-when-needed',
+                          'extra-allowed: [^ftp://]',
+                          'extra-required: [^http://]'])
+        self.check('---\n'
+                   '123: 2\n'
+                   '"234": 3\n'
+                   'localhost: 4\n'
+                   '"host.local": 5\n'           # fails
+                   'http://localhost: 6\n'       # fails
+                   '"http://host.local": 7\n'
+                   'ftp://localhost: 8\n'
+                   '"ftp://host.local": 9\n',
+                   conf, problem1=(5, 1), problem2=(6, 1))
+
+        conf = self.conf(['required: false',
+                          'extra-required: [^http://, ^ftp://]'])
+        self.check('---\n'
+                   '123: 2\n'
+                   '"234": 3\n'
+                   'localhost: 4\n'
+                   '"host.local": 5\n'
+                   'http://localhost: 6\n'       # fails
+                   '"http://host.local": 7\n'
+                   'ftp://localhost: 8\n'        # fails
+                   '"ftp://host.local": 9\n',
+                   conf, problem1=(6, 1), problem2=(8, 1))
+
+        conf = self.conf(['required: only-when-needed',
+                          'extra-allowed: [^ftp://, ";$", " "]'])
+        self.check('---\n'
+                   'localhost: 2\n'
+                   '"host.local": 3\n'           # fails
+                   'ftp://localhost: 4\n'
+                   '"ftp://host.local": 5\n'
+                   'i=i+1: 6\n'
+                   '"i=i+2": 7\n'                # fails
+                   'i=i+3;: 8\n'
+                   '"i=i+4;": 9\n'
+                   'foo1: 10\n'
+                   '"foo2": 11\n'                # fails
+                   'foo bar1: 12\n'
+                   '"foo bar2": 13\n',
+                   conf, problem1=(3, 1), problem2=(7, 1), problem3=(11, 1))
+
+    def test_octal_values(self):
+        conf = self.conf(['required: true'])
+
+        self.check('---\n'
+                   '100: 2\n'
+                   '0100: 3\n'
+                   '0o100: 4\n'
+                   '777: 5\n'
+                   '0777: 6\n'
+                   '0o777: 7\n'
+                   '800: 8\n'
+                   '0800: 9\n'                  # fails
+                   '0o800: 10\n'                # fails
+                   '"0900": 11\n'
+                   '"0o900": 12\n',
+                   conf,
+                   problem1=(9, 1), problem2=(10, 1))
+
+    def test_allow_quoted_quotes(self):
+        conf = self.conf(['quote-type: single',
+                          'required: false',
+                          'allow-quoted-quotes: false'])
+        self.check('---\n'
+                   '"[barbaz]": 2\n'            # fails
+                   '"[bar\'baz]": 3\n',         # fails
+                   conf, problem1=(2, 1), problem2=(3, 1))
+
+        conf = self.conf(['quote-type: single',
+                          'required: false',
+                          'allow-quoted-quotes: true'])
+        self.check('---\n'
+                   '"[barbaz]": 2\n'            # fails
+                   '"[bar\'baz]": 3\n',
+                   conf, problem1=(2, 1))
+
+        conf = self.conf(['quote-type: single',
+                          'required: true',
+                          'allow-quoted-quotes: false'])
+        self.check('---\n'
+                   '"[barbaz]": 2\n'            # fails
+                   '"[bar\'baz]": 3\n',         # fails
+                   conf, problem1=(2, 1), problem2=(3, 1))
+
+        conf = self.conf(['quote-type: single',
+                          'required: true',
+                          'allow-quoted-quotes: true'])
+        self.check('---\n'
+                   '"[barbaz]": 2\n'            # fails
+                   '"[bar\'baz]": 3\n',
+                   conf, problem1=(2, 1))
+
+        conf = self.conf(['quote-type: single',
+                          'required: only-when-needed',
+                          'allow-quoted-quotes: false'])
+        self.check('---\n'
+                   '"[barbaz]": 2\n'            # fails
+                   '"[bar\'baz]": 3\n',         # fails
+                   conf, problem1=(2, 1), problem2=(3, 1))
+
+        conf = self.conf(['quote-type: single',
+                          'required: only-when-needed',
+                          'allow-quoted-quotes: true'])
+        self.check('---\n'
+                   '"[barbaz]": 2\n'            # fails
+                   '"[bar\'baz]": 3\n',
+                   conf, problem1=(2, 1))
+
+        conf = self.conf(['quote-type: double',
+                          'required: false',
+                          'allow-quoted-quotes: false'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"            # fails
+                   "'[bar\"baz]': 3\n",         # fails
+                   conf, problem1=(2, 1), problem2=(3, 1))
+
+        conf = self.conf(['quote-type: double',
+                          'required: false',
+                          'allow-quoted-quotes: true'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"            # fails
+                   "'[bar\"baz]': 3\n",
+                   conf, problem1=(2, 1))
+
+        conf = self.conf(['quote-type: double',
+                          'required: true',
+                          'allow-quoted-quotes: false'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"            # fails
+                   "'[bar\"baz]': 3\n",         # fails
+                   conf, problem1=(2, 1), problem2=(3, 1))
+
+        conf = self.conf(['quote-type: double',
+                          'required: true',
+                          'allow-quoted-quotes: true'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"            # fails
+                   "'[bar\"baz]': 3\n",
+                   conf, problem1=(2, 1))
+
+        conf = self.conf(['quote-type: double',
+                          'required: only-when-needed',
+                          'allow-quoted-quotes: false'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"            # fails
+                   "'[bar\"baz]': 3\n",         # fails
+                   conf, problem1=(2, 1), problem2=(3, 1))
+
+        conf = self.conf(['quote-type: double',
+                          'required: only-when-needed',
+                          'allow-quoted-quotes: true'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"            # fails
+                   "'[bar\"baz]': 3\n",
+                   conf, problem1=(2, 1))
+
+        conf = self.conf(['quote-type: any'])
+        self.check("---\n"
+                   "'[barbaz]': 2\n"
+                   "'[bar\"baz]': 3\n",
+                   conf)
diff --git a/yamllint/rules/common.py b/yamllint/rules/common.py
index 06f560c0..395000e5 100644
--- a/yamllint/rules/common.py
+++ b/yamllint/rules/common.py
@@ -86,3 +86,7 @@ def is_explicit_key(token):
     #   : v
     return (token.start_mark.pointer < token.end_mark.pointer and
             token.start_mark.buffer[token.start_mark.pointer] == '?')
+
+
+def is_key(token):
+    return token and isinstance(token, yaml.KeyToken)
diff --git a/yamllint/rules/quoted_strings.py b/yamllint/rules/quoted_strings.py
index 86b825e0..77ada7ea 100644
--- a/yamllint/rules/quoted_strings.py
+++ b/yamllint/rules/quoted_strings.py
@@ -32,6 +32,9 @@
   even if ``required: only-when-needed`` is set.
 * ``allow-quoted-quotes`` allows (``true``) using disallowed quotes for strings
   with allowed quotes inside. Default ``false``.
+* ``check-keys`` defines whether to apply the rules to keys in mappings. By
+  default, ``quoted-strings`` rules apply only to values. Set this option to
+  ``true`` to apply the rules to keys as well.
 
 **Note**: Multi-line strings (with ``|`` or ``>``) will not be checked.
 
@@ -46,6 +49,7 @@
      extra-required: []
      extra-allowed: []
      allow-quoted-quotes: false
+     check-keys: false
 
 .. rubric:: Examples
 
@@ -135,6 +139,19 @@
 
     foo: 'bar"baz'
 
+#. With ``quoted-strings: {required: only-when-needed, check-keys: true,
+   extra-required: ["[:]"]}``
+
+   the following code snippet would **FAIL**:
+   ::
+
+    foo:bar: baz
+
+   the following code snippet would **PASS**:
+   ::
+
+    "foo:bar": baz
+
 """
 
 import re
@@ -142,6 +159,7 @@
 import yaml
 
 from yamllint.linter import LintProblem
+from yamllint.rules.common import is_key
 
 ID = 'quoted-strings'
 TYPE = 'token'
@@ -149,12 +167,14 @@
         'required': (True, False, 'only-when-needed'),
         'extra-required': [str],
         'extra-allowed': [str],
-        'allow-quoted-quotes': bool}
+        'allow-quoted-quotes': bool,
+        'check-keys': bool}
 DEFAULT = {'quote-type': 'any',
            'required': True,
            'extra-required': [],
            'extra-allowed': [],
-           'allow-quoted-quotes': False}
+           'allow-quoted-quotes': False,
+           'check-keys': False}
 
 
 def VALIDATE(conf):
@@ -226,10 +246,17 @@ def check(conf, token, prev, next, nextnext, context):
     if not (isinstance(token, yaml.tokens.ScalarToken) and
             isinstance(prev, (yaml.BlockEntryToken, yaml.FlowEntryToken,
                               yaml.FlowSequenceStartToken, yaml.TagToken,
-                              yaml.ValueToken))):
+                              yaml.ValueToken, yaml.KeyToken))):
 
         return
 
+    if is_key(prev):
+        if not conf['check-keys']:
+            return
+        node = 'key'
+    else:
+        node = 'value'
+
     # Ignore explicit types, e.g. !!str testtest or !!int 42
     if (prev and isinstance(prev, yaml.tokens.TagToken) and
             prev.value[0] == '!!'):
@@ -254,7 +281,7 @@ def check(conf, token, prev, next, nextnext, context):
         if (token.style is None or
             not (_quote_match(quote_type, token.style) or
                  (conf['allow-quoted-quotes'] and _has_quoted_quotes(token)))):
-            msg = f"string value is not quoted with {quote_type} quotes"
+            msg = f"string {node} is not quoted with {quote_type} quotes"
 
     elif conf['required'] is False:
 
@@ -263,13 +290,13 @@ def check(conf, token, prev, next, nextnext, context):
                 not _quote_match(quote_type, token.style) and
                 not (conf['allow-quoted-quotes'] and
                      _has_quoted_quotes(token))):
-            msg = f"string value is not quoted with {quote_type} quotes"
+            msg = f"string {node} is not quoted with {quote_type} quotes"
 
         elif not token.style:
             is_extra_required = any(re.search(r, token.value)
                                     for r in conf['extra-required'])
             if is_extra_required:
-                msg = "string value is not quoted"
+                msg = f"string {node} is not quoted"
 
     elif conf['required'] == 'only-when-needed':
 
@@ -282,14 +309,14 @@ def check(conf, token, prev, next, nextnext, context):
             is_extra_allowed = any(re.search(r, token.value)
                                    for r in conf['extra-allowed'])
             if not (is_extra_required or is_extra_allowed):
-                msg = f"string value is redundantly quoted with " \
+                msg = f"string {node} is redundantly quoted with " \
                       f"{quote_type} quotes"
 
         # But when used need to match config
         elif (token.style and
               not _quote_match(quote_type, token.style) and
               not (conf['allow-quoted-quotes'] and _has_quoted_quotes(token))):
-            msg = f"string value is not quoted with {quote_type} quotes"
+            msg = f"string {node} is not quoted with {quote_type} quotes"
 
         elif not token.style:
             is_extra_required = len(conf['extra-required']) and any(