diff --git a/LEGAL b/LEGAL
index cd1cce2de1..8080cfef61 100644
--- a/LEGAL
+++ b/LEGAL
@@ -12,7 +12,7 @@ ccan/str/str.h
 
   These files are licensed under the CC0.
 
-    http://creativecommons.org/choose/zero/
+    https://creativecommons.org/choose/zero/
 
 ccan/list/list.h
 
diff --git a/README.ja.md b/README.ja.md
index 9d6131e416..e98612a2b7 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -18,7 +18,7 @@ Rubyはテキスト処理関係の能力などに優れ，Perlと同じくらい
 *   ダイナミックローディング (アーキテクチャによる)
 *   移植性が高い．多くのUnix-like/POSIX互換プラットフォーム上で動くだけでなく，Windows， Mac OS
     X，BeOSなどの上でも動く cf.
-    http://bugs.ruby-lang.org/projects/ruby-trunk/wiki/SupportedPlatformsJa
+    https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/SupportedPlatformsJa
 
 
 ## 入手法
@@ -33,11 +33,11 @@ ftp://ftp.ruby-lang.org/pub/ruby/
 
 開発先端のソースコードは次のコマンドで取得できます．
 
-    $ svn co http://svn.ruby-lang.org/repos/ruby/trunk/ ruby
+    $ svn co https://svn.ruby-lang.org/repos/ruby/trunk/ ruby
 
 他に開発中のブランチの一覧は次のコマンドで見られます．
 
-    $ svn ls http://svn.ruby-lang.org/repos/ruby/branches/
+    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
 
 ### Gitで
 
@@ -49,7 +49,7 @@ SubversionのミラーをGitHubに公開しています． 以下のコマンド
 
 RubyのホームページのURLは
 
-http://www.ruby-lang.org/
+https://www.ruby-lang.org/
 
 です．
 
@@ -156,9 +156,9 @@ UNIXであれば `configure` がほとんどの差異を吸収してくれるは
 ## フィードバック
 
 Rubyに関する質問は Ruby-Talk（英語）や Ruby-List（日本語） (https://www.ruby-lang.org/ja/community/mailing-lists) や，
-stackoverflow (http://ja.stackoverflow.com/) などのWebサイトに投稿してください．
+stackoverflow (https://ja.stackoverflow.com/) などのWebサイトに投稿してください．
 
-バグ報告は http://bugs.ruby-lang.org で受け付けています．
+バグ報告は https://bugs.ruby-lang.org で受け付けています．
 
 
 ## 著者
diff --git a/README.md b/README.md
index f79ba9c718..194487fdb0 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ extensible.
 *   Dynamic Loading of Object Files (on some architectures)
 *   Highly Portable (works on many Unix-like/POSIX compatible platforms as
     well as Windows, Mac OS X, BeOS, etc.) cf.
-    http://bugs.ruby-lang.org/projects/ruby-trunk/wiki/SupportedPlatforms
+    https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/SupportedPlatforms
 
 
 ## How to get Ruby
@@ -28,7 +28,7 @@ extensible.
 For a complete list of ways to install Ruby, including using third-party tools
 like rvm, see:
 
-http://www.ruby-lang.org/en/downloads/
+https://www.ruby-lang.org/en/downloads/
 
 The Ruby distribution files can be found on the following FTP site:
 
@@ -37,7 +37,7 @@ ftp://ftp.ruby-lang.org/pub/ruby/
 The trunk of the Ruby source tree can be checked out with the following
 command:
 
-    $ svn co http://svn.ruby-lang.org/repos/ruby/trunk/ ruby
+    $ svn co https://svn.ruby-lang.org/repos/ruby/trunk/ ruby
 
 Or if you are using git then use the following command:
 
@@ -46,7 +46,7 @@ Or if you are using git then use the following command:
 There are some other branches under development.  Try the following command
 to see the list of branches:
 
-    $ svn ls http://svn.ruby-lang.org/repos/ruby/branches/
+    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
 
 Or if you are using git then use the following command:
 
@@ -56,7 +56,7 @@ Or if you are using git then use the following command:
 
 The URL of the Ruby home page is:
 
-http://www.ruby-lang.org/
+https://www.ruby-lang.org/
 
 ## Mailing list
 
@@ -147,10 +147,10 @@ See the file [COPYING](COPYING).
 ## Feedback
 
 Questions about the Ruby language can be asked on the Ruby-Talk mailing list
-(http://www.ruby-lang.org/en/community/mailing-lists) or on websites like
-(http://stackoverflow.com).
+(https://www.ruby-lang.org/en/community/mailing-lists) or on websites like
+(https://stackoverflow.com).
 
-Bug reports should be filed at http://bugs.ruby-lang.org. Read [HowToReport] for more information.
+Bug reports should be filed at https://bugs.ruby-lang.org. Read [HowToReport] for more information.
 
 [HowToReport]: https://bugs.ruby-lang.org/projects/ruby/wiki/HowToReport
 
diff --git a/doc/contributing.rdoc b/doc/contributing.rdoc
index 75d00e6f9f..d0340d4d82 100644
--- a/doc/contributing.rdoc
+++ b/doc/contributing.rdoc
@@ -11,7 +11,7 @@ trying out beta releases with your applications.
 == How To Report
 
 If you've encountered a bug in Ruby please report it to the redmine issue
-tracker available at {bugs.ruby-lang.org}[http://bugs.ruby-lang.org/].  Do not
+tracker available at {bugs.ruby-lang.org}[https://bugs.ruby-lang.org/].  Do not
 report security vulnerabilities here, there is a {separate
 channel}[rdoc-label:label-Reporting+Security+Issues] for them.
 
@@ -25,7 +25,7 @@ on your ticket.
 
   If you aren't already using the latest version, try installing a newer
   stable release. See
-  {Downloading Ruby}[http://www.ruby-lang.org/en/downloads/].
+  {Downloading Ruby}[https://www.ruby-lang.org/en/downloads/].
 * Look to see if anyone already reported your issue, try
   {searching on redmine}[https://bugs.ruby-lang.org/projects/ruby-trunk/issues]
   for your problem.
@@ -94,7 +94,7 @@ affect many users. There is a private mailing list that all security issues
 should be reported to and will be handled discretely. Email the
 mailto:security@ruby-lang.org list and the problem will be published after
 fixes have been released. You can also encrypt the issue using {the PGP public
-key}[http://www.ruby-lang.org/security.asc] for the list.
+key}[https://www.ruby-lang.org/security.asc] for the list.
 
 == Reporting Other Issues
 
@@ -253,7 +253,7 @@ CRuby uses subversion for source control, you can find installation
 instructions and lots of great info to learn subversion on the
 {svnbook.red-bean.com}[http://svnbook.red-bean.com/]. For other resources see
 the {ruby-core documentation on
-ruby-lang.org}[http://www.ruby-lang.org/en/community/ruby-core/].
+ruby-lang.org}[https://www.ruby-lang.org/en/community/ruby-core/].
 
 This guide will use git for contributing.  The {git
 homepage}[http://git-scm.com/] has installation instructions with links to
diff --git a/doc/security.rdoc b/doc/security.rdoc
index 378699fb15..d7d6464ce1 100644
--- a/doc/security.rdoc
+++ b/doc/security.rdoc
@@ -7,12 +7,12 @@ This document aims to discuss many of these pitfalls and provide more secure
 alternatives where applicable.
 
 Please check the full list of publicly known CVEs and how to correctly report a
-security vulnerability, at: http://www.ruby-lang.org/en/security/
-Japanese version is here: http://www.ruby-lang.org/ja/security/
+security vulnerability, at: https://www.ruby-lang.org/en/security/
+Japanese version is here: https://www.ruby-lang.org/ja/security/
 
 Security vulnerabilities should be reported via an email to
 mailto:security@ruby-lang.org ({the PGP public
-key}[http://www.ruby-lang.org/security.asc]), which is a private mailing list.
+key}[https://www.ruby-lang.org/security.asc]), which is a private mailing list.
 Reported problems will be published after fixes.
 
 == <code>$SAFE</code>
diff --git a/doc/syntax/refinements.rdoc b/doc/syntax/refinements.rdoc
index 4cba61d396..1419fea509 100644
--- a/doc/syntax/refinements.rdoc
+++ b/doc/syntax/refinements.rdoc
@@ -257,6 +257,6 @@ This behavior may be changed in the future.
 
 == Further Reading
 
-See http://bugs.ruby-lang.org/projects/ruby-trunk/wiki/RefinementsSpec for the
+See https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/RefinementsSpec for the
 current specification for implementing refinements.  The specification also
 contains more details.
diff --git a/ext/bigdecimal/bigdecimal.gemspec b/ext/bigdecimal/bigdecimal.gemspec
index 1666325d45..e7acfe2d11 100644
--- a/ext/bigdecimal/bigdecimal.gemspec
+++ b/ext/bigdecimal/bigdecimal.gemspec
@@ -8,7 +8,7 @@ Gem::Specification.new do |s|
   s.date = date
   s.license = 'ruby'
   s.summary = "Arbitrary-precision decimal floating-point number library."
-  s.homepage = "http://www.ruby-lang.org"
+  s.homepage = "https://www.ruby-lang.org"
   s.email = "mrkn@mrkn.jp"
   s.description = "This library provides arbitrary-precision decimal floating-point number class."
   s.authors = ["Kenta Murata", "Zachary Scott", "Shigeo Kobayashi"]
diff --git a/ext/io/console/io-console.gemspec b/ext/io/console/io-console.gemspec
index d7414bb706..27e1a11e3a 100644
--- a/ext/io/console/io-console.gemspec
+++ b/ext/io/console/io-console.gemspec
@@ -10,7 +10,7 @@ Gem::Specification.new do |s|
   s.email = "nobu@ruby-lang.org"
   s.description = "add console capabilities to IO instances."
   s.required_ruby_version = ">= 2.0.0"
-  s.homepage = "http://www.ruby-lang.org"
+  s.homepage = "https://www.ruby-lang.org"
   s.authors = ["Nobu Nakada"]
   s.require_path = %[lib]
   s.files = %w[console.c depend extconf.rb lib/console/size.rb win32_vk.inc]
diff --git a/man/erb.1 b/man/erb.1
index 05d8f5634b..9fe73c1594 100644
--- a/man/erb.1
+++ b/man/erb.1
@@ -149,7 +149,7 @@ class.
 Reported problems will be published after being fixed.
 .Pp
 .Li And you can report other bugs and feature requests via the
-Ruby Issue Tracking System (http://bugs.ruby-lang.org).
+Ruby Issue Tracking System (https://bugs.ruby-lang.org).
 Do not report security vulnerabilities
 via the system because it publishes the vulnerabilities immediately.
 .El
diff --git a/man/irb.1 b/man/irb.1
index 62bd714ddc..a2787ce4a3 100644
--- a/man/irb.1
+++ b/man/irb.1
@@ -165,7 +165,7 @@ Personal irb initialization.
 Reported problems will be published after being fixed.
 .Pp
 .Li And you can report other bugs and feature requests via the
-Ruby Issue Tracking System (http://bugs.ruby-lang.org).
+Ruby Issue Tracking System (https://bugs.ruby-lang.org).
 Do not report security vulnerabilities
 via the system because it publishes the vulnerabilities immediately.
 .El
diff --git a/man/ri.1 b/man/ri.1
index bf4efb1ac3..df55746162 100644
--- a/man/ri.1
+++ b/man/ri.1
@@ -172,7 +172,7 @@ Searches user-wide documents here.
 Reported problems will be published after being fixed.
 .Pp
 .Li And you can report other bugs and feature requests via the
-Ruby Issue Tracking System (http://bugs.ruby-lang.org).
+Ruby Issue Tracking System (https://bugs.ruby-lang.org).
 Do not report security vulnerabilities
 via the system because it publishes the vulnerabilities immediately.
 .El
diff --git a/man/ruby.1 b/man/ruby.1
index 36039fecce..75efb79e66 100644
--- a/man/ruby.1
+++ b/man/ruby.1
@@ -623,7 +623,7 @@ default: 262144 or 524288
 .Pp
 .El
 .Sh SEE ALSO
-.Bl -hang -compact -width "http://www.ruby-lang.org/123"
+.Bl -hang -compact -width "https://www.ruby-lang.org/123"
 .It https://www.ruby-lang.org/
 The official web site.
 .It https://www.ruby-toolbox.com/
diff --git a/misc/ruby-additional.el b/misc/ruby-additional.el
index 07f7199226..a70aa7d54f 100644
--- a/misc/ruby-additional.el
+++ b/misc/ruby-additional.el
@@ -1,7 +1,7 @@
 ;;; ruby-additional.el --- ruby-mode extensions yet to be merged into Emacs
 
 ;; Authors: Yukihiro Matsumoto, Nobuyoshi Nakada, Akinori MUSHA
-;; URL: http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/trunk/misc/
+;; URL: https://svn.ruby-lang.org/cgi-bin/viewvc.cgi/trunk/misc/
 ;; Created: 3 Sep 2012
 ;; Package-Requires: ((emacs "24.3") (ruby-mode "1.2"))
 ;; Keywords: ruby, languages
diff --git a/template/ruby.pc.in b/template/ruby.pc.in
index 8a2c066e9c..2b68f59776 100644
--- a/template/ruby.pc.in
+++ b/template/ruby.pc.in
@@ -50,7 +50,7 @@ DLDFLAGS=@DLDFLAGS@
 Name: Ruby
 Description: Object Oriented Script Language
 Version: ${ruby_version}
-URL: http://www.ruby-lang.org
+URL: https://www.ruby-lang.org
 Cflags: -I${rubyarchhdrdir} -I${rubyhdrdir}
 Libs: ${DLDFLAGS} ${LIBRUBYARG_SHARED} ${LIBS}
 Requires: