diff --git a/lib/ransack/constants.rb b/lib/ransack/constants.rb
index b8a9838..863222b 100644
--- a/lib/ransack/constants.rb
+++ b/lib/ransack/constants.rb
@@ -55,6 +55,14 @@ module Ransack
         :formatter => proc { |v| true }
         }
       ],
+      ['not_true', {
+        :arel_predicate => proc { |v| v ? 'not_eq' : 'eq' },
+        :compounds => false,
+        :type => :boolean,
+        :validator => proc { |v| BOOLEAN_VALUES.include?(v) },
+        :formatter => proc { |v| true }
+        }
+      ],
       ['false', {
         :arel_predicate => proc { |v| v ? 'eq' : 'not_eq' },
         :compounds => false,
@@ -63,6 +71,14 @@ module Ransack
         :formatter => proc { |v| false }
         }
       ],
+      ['not_false', {
+        :arel_predicate => proc { |v| v ? 'not_eq' : 'eq' },
+        :compounds => false,
+        :type => :boolean,
+        :validator => proc { |v| BOOLEAN_VALUES.include?(v) },
+        :formatter => proc { |v| false }
+        }
+      ],
       ['present', {
         :arel_predicate => proc { |v| v ? 'not_eq_all' : 'eq_any' },
         :compounds => false,
diff --git a/spec/ransack/predicate_spec.rb b/spec/ransack/predicate_spec.rb
index 49436d7..6c64a20 100644
--- a/spec/ransack/predicate_spec.rb
+++ b/spec/ransack/predicate_spec.rb
@@ -96,6 +96,22 @@ module Ransack
       end
     end
 
+    describe 'not_true' do
+      it 'generates an inequality condition for boolean true' do
+        @s.awesome_not_true = true
+        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
+        expect(@s.result.to_sql).to match /#{field} != #{
+          ActiveRecord::Base.connection.quoted_true}/
+      end
+
+      it 'generates an equality condition for boolean true' do
+        @s.awesome_not_true = false
+        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
+        expect(@s.result.to_sql).to match /#{field} = #{
+          ActiveRecord::Base.connection.quoted_true}/
+      end
+    end
+
     describe 'false' do
       it 'generates an equality condition for boolean false' do
         @s.awesome_false = true
@@ -112,6 +128,22 @@ module Ransack
       end
     end
 
+    describe 'not_false' do
+      it 'generates an inequality condition for boolean false' do
+        @s.awesome_not_false = true
+        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
+        expect(@s.result.to_sql).to match /#{field} != #{
+          ActiveRecord::Base.connection.quoted_false}/
+      end
+
+      it 'generates an equality condition for boolean false' do
+        @s.awesome_not_false = false
+        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
+        expect(@s.result.to_sql).to match /#{field} = #{
+          ActiveRecord::Base.connection.quoted_false}/
+      end
+    end
+
     describe 'null' do
       it 'generates a value IS NULL query' do
         @s.name_null = true