diff --git a/cloudbot/util/text.py b/cloudbot/util/text.py
new file mode 100644
index 000000000..5ff7d00e3
--- /dev/null
+++ b/cloudbot/util/text.py
@@ -0,0 +1,49 @@
+from typing import Optional
+
+__all__ = ('parse_bool',)
+
+_STR_TO_BOOL = {
+    "yes": True,
+    "y": True,
+    "no": False,
+    "n": False,
+    "on": True,
+    "off": False,
+    "enable": True,
+    "disable": False,
+    "allow": True,
+    "deny": False,
+    "true": True,
+    "false": False,
+}
+
+
+def parse_bool(s: str, *, fail_on_unknown: bool = True) -> Optional[bool]:
+    """
+    Parse a string to a boolean value
+
+    >>> parse_bool('true')
+    True
+    >>> parse_bool('yes')
+    True
+    >>> parse_bool('no')
+    False
+    >>> parse_bool('maybe', fail_on_unknown=False)
+    >>> parse_bool('maybe')
+    Traceback (most recent call last):
+        [...]
+    KeyError: 'maybe'
+
+    :param s: The string to parse
+    :param fail_on_unknown: Whether to raise an error if the input can't
+        be parsed
+    :return: The parsed value
+    """
+
+    try:
+        return _STR_TO_BOOL[s.lower()]
+    except KeyError:
+        if fail_on_unknown:
+            raise
+
+        return None
diff --git a/plugins/core/optout.py b/plugins/core/optout.py
index 846a3c750..fc7334f4d 100644
--- a/plugins/core/optout.py
+++ b/plugins/core/optout.py
@@ -13,6 +13,7 @@
 from cloudbot.util import database, web
 from cloudbot.util.formatting import gen_markdown_table
 from cloudbot.util.mapping import DefaultKeyFoldDict
+from cloudbot.util.text import parse_bool
 
 optout_table = Table(
     'optout',
@@ -129,20 +130,6 @@ def clear_optout(db, conn, chan=None):
     return res.rowcount
 
 
-_STR_TO_BOOL = {
-    "yes": True,
-    "y": True,
-    "no": False,
-    "n": False,
-    "on": True,
-    "off": False,
-    "enable": True,
-    "disable": False,
-    "allow": True,
-    "deny": False,
-}
-
-
 @hook.onload
 def load_cache(db):
     new_cache = defaultdict(list)
@@ -206,7 +193,7 @@ async def optout(text, event, chan, db, conn):
     if args:
         allow = args.pop(0)
         try:
-            allowed = _STR_TO_BOOL[allow.lower()]
+            allowed = parse_bool(allow)
         except KeyError:
             return "Invalid allow option."