diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index 90fb34e386679aff2f7dec8e2e017f6490177a06..1735609cd938dad0dc371e731d6f7b74723e50b5 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -103,7 +103,7 @@ module ClassMethods
       #
       # Both <tt>ActionController::Base</tt> and <tt>ActionController::API</tt>
       # include <tt>ActionController::Renderers::All</tt>, making all renderers
-      # avaialable in the controller. See <tt>Renderers::RENDERERS</tt> and <tt>Renderers.add</tt>.
+      # available in the controller. See <tt>Renderers::RENDERERS</tt> and <tt>Renderers.add</tt>.
       #
       # Since <tt>ActionController::Metal</tt> controllers cannot render, the controller
       # must include <tt>AbstractController::Rendering</tt>, <tt>ActionController::Rendering</tt>,
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index e3793e6c778cf97238dd0921257d66f29d65b672..eb2268157b011130489798398e0731b7958fa100 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -541,7 +541,7 @@ def table_structure_with_collation(table_name, basic_structure)
           result = exec_query(sql, 'SCHEMA').first
 
           if result
-            # Splitting with left parantheses and picking up last will return all
+            # Splitting with left parentheses and picking up last will return all
             # columns separated with comma(,).
             columns_string = result["sql"].split('(').last
 
diff --git a/activerecord/test/cases/connection_adapters/type_lookup_test.rb b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
index 7566863653394556413cabe8291ebe98e01a1784..3acbafbff4cd5114d732057fc61461b0d63d2b51 100644
--- a/activerecord/test/cases/connection_adapters/type_lookup_test.rb
+++ b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
@@ -1,6 +1,6 @@
 require "cases/helper"
 
-unless current_adapter?(:PostgreSQLAdapter) # PostgreSQL does not use type strigns for lookup
+unless current_adapter?(:PostgreSQLAdapter) # PostgreSQL does not use type strings for lookup
 module ActiveRecord
   module ConnectionAdapters
     class TypeLookupTest < ActiveRecord::TestCase
diff --git a/activerecord/test/cases/scoping/named_scoping_test.rb b/activerecord/test/cases/scoping/named_scoping_test.rb
index f05df9d76be37dc5e77bdafbd9895385e4c4d197..0e277ed23511699ebab7f388b4dc68c6858c36cb 100644
--- a/activerecord/test/cases/scoping/named_scoping_test.rb
+++ b/activerecord/test/cases/scoping/named_scoping_test.rb
@@ -301,7 +301,7 @@ def pro; end
       :relation,      # private class method on AR::Base
       :new,           # redefined class method on AR::Base
       :all,           # a default scope
-      :public,        # some imporant methods on Module and Class
+      :public,        # some important methods on Module and Class
       :protected,
       :private,
       :name,
diff --git a/activesupport/test/core_ext/object/json_gem_encoding_test.rb b/activesupport/test/core_ext/object/json_gem_encoding_test.rb
index 02ab17fb640a4452ce7e8a5854a71cf8be95088b..2cbb1d590f02a23fddb565c07ec86025f3d79b98 100644
--- a/activesupport/test/core_ext/object/json_gem_encoding_test.rb
+++ b/activesupport/test/core_ext/object/json_gem_encoding_test.rb
@@ -10,7 +10,7 @@
 
 # The AS::JSON encoder requires the BigDecimal core_ext, which, unfortunately,
 # changes the BigDecimal#to_s output, and consequently the JSON gem output. So
-# we need to require this unfront to ensure we don't get a false failure, but
+# we need to require this upfront to ensure we don't get a false failure, but
 # ideally we should just fix the BigDecimal core_ext to not change to_s without
 # arguments.
 require 'active_support/core_ext/big_decimal'
diff --git a/ci/travis.rb b/ci/travis.rb
index 063c6acb070b9e454a6a87ad831863e043107b8d..ffeba995debc8cc807394d95441ff2decc7e645a 100755
--- a/ci/travis.rb
+++ b/ci/travis.rb
@@ -120,7 +120,7 @@ def rake(*tasks)
 
   def env
     if activesupport? && !isolated?
-      # There is a known issue with the listen tests that casuses files to be
+      # There is a known issue with the listen tests that causes files to be
       # incorrectly GC'ed even when they are still in-use. The current is to
       # only run them in isolation to avoid randomly failing our test suite.
       { 'LISTEN' => '0' }
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 5757d235d278f9c4dce7a230ea07e42fb17146bb..9701409755a3ed4b1b08c2f22bec87ff8c323ac6 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -219,7 +219,7 @@ module Rails
   # The next thing that changes in isolated engines is the behavior of routes.
   # Normally, when you namespace your controllers, you also need to namespace
   # the related routes. With an isolated engine, the engine's namespace is
-  # automatically applied, so you don't need to specify it explicity in your
+  # automatically applied, so you don't need to specify it explicitly in your
   # routes:
   #
   #   MyEngine::Engine.routes.draw do
diff --git a/railties/test/application/configuration_test.rb b/railties/test/application/configuration_test.rb
index 1ca6bbcecf470f3a7b2550ff04f6a2c5432d867d..9f3a9cd232dec276bef0b7003e0e36ecfe2ac467 100644
--- a/railties/test/application/configuration_test.rb
+++ b/railties/test/application/configuration_test.rb
@@ -686,7 +686,7 @@ def update
 
         private
 
-        def form_authenticity_token(*args); token; end # stub the authenticy token
+        def form_authenticity_token(*args); token; end # stub the authenticity token
       end
       RUBY