diff --git a/CHANGELOG.asciidoc b/CHANGELOG.asciidoc
index 5dcbc356b..bd663f8a8 100644
--- a/CHANGELOG.asciidoc
+++ b/CHANGELOG.asciidoc
@@ -91,6 +91,7 @@ Fixed
 - Fixed handling of backspace in number hinting mode
 - Fixed `FileNotFoundError` when starting in some cases on old Qt versions
 - Fixed sharing of cookies between tabs when `private-browsing` is enabled
+- Toggling values with `:set` now uses lower-case values
 
 v0.6.2
 ------
diff --git a/README.asciidoc b/README.asciidoc
index 2f63f11d1..8e4a2bf15 100644
--- a/README.asciidoc
+++ b/README.asciidoc
@@ -177,6 +177,7 @@ Contributors, sorted by the number of commits in descending order:
 * Liam BEGUIN
 * skinnay
 * Zach-Button
+* Tomasz Kramkowski
 * Halfwit
 * rikn00
 * kanikaa1234
@@ -188,7 +189,6 @@ Contributors, sorted by the number of commits in descending order:
 * sbinix
 * neeasade
 * jnphilipp
-* Tomasz Kramkowski
 * Tobias Patzl
 * Stefan Tatschner
 * Peter Michely
diff --git a/qutebrowser/config/config.py b/qutebrowser/config/config.py
index b66ef2969..f788bb7ca 100644
--- a/qutebrowser/config/config.py
+++ b/qutebrowser/config/config.py
@@ -734,7 +734,7 @@ class ConfigManager(QObject):
                     val = self.get(section_, option)
                     layer = 'temp' if temp else 'conf'
                     if isinstance(val, bool):
-                        self.set(layer, section_, option, str(not val))
+                        self.set(layer, section_, option, str(not val).lower())
                     else:
                         raise cmdexc.CommandError(
                             "set: Attempted inversion of non-boolean value.")
diff --git a/tests/end2end/features/set.feature b/tests/end2end/features/set.feature
index edb455abe..aabb07f7e 100644
--- a/tests/end2end/features/set.feature
+++ b/tests/end2end/features/set.feature
@@ -26,7 +26,7 @@ Feature: Setting settings.
     Scenario: Toggling an option
         When I run :set general auto-save-config false
         And I run :set general auto-save-config!
-        Then general -> auto-save-config should be True
+        Then general -> auto-save-config should be true
 
     Scenario: Toggling a non-bool option
         When I run :set colors statusbar.bg!
@@ -44,7 +44,7 @@ Feature: Setting settings.
     Scenario: Using ! and -p
         When I run :set general auto-save-config false
         And I run :set -p general auto-save-config!
-        Then the message "general auto-save-config = True" should be shown
+        Then the message "general auto-save-config = true" should be shown
 
     Scenario: Setting an invalid value
         When I run :set general auto-save-config blah