diff --git a/INSTALL b/INSTALL
index 67df1880..7fb41fa6 100644
--- a/INSTALL
+++ b/INSTALL
@@ -596,7 +596,7 @@ XZ Utils Installation
     a fallback xzdiff will use mkdir to securely create a temporary
     directory. Having mktemp available is still recommended since the
     mkdir fallback method isn't as robust as mktemp is. The original
-    mktemp can be found from <http://www.mktemp.org/>. On GNU, most will
+    mktemp can be found from <https://www.mktemp.org/>. On GNU, most will
     use the mktemp program from GNU coreutils instead of the original
     implementation. Both mktemp versions are fine.
 
diff --git a/README b/README
index b9081ed4..ed1cace1 100644
--- a/README
+++ b/README
@@ -113,8 +113,8 @@ XZ Utils
     Since the liblzma API has similarities to the zlib API, some people
     may find it useful to read the zlib docs and tutorial too:
 
-        http://zlib.net/manual.html
-        http://zlib.net/zlib_how.html
+        https://zlib.net/manual.html
+        https://zlib.net/zlib_how.html
 
 
 2. Version numbering
@@ -281,8 +281,8 @@ XZ Utils
     7-Zip and the p7zip port of 7-Zip support the .xz format starting
     from the version 9.00alpha.
 
-        http://7-zip.org/
-        http://p7zip.sourceforge.net/
+        https://7-zip.org/
+        https://p7zip.sourceforge.net/
 
     XZ Embedded is a limited implementation written for use in the Linux
     kernel, but it is also suitable for other embedded use.
diff --git a/configure.ac b/configure.ac
index 631b1877..d8811b9b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -596,7 +596,7 @@ echo "Initializing Automake:"
 
 # We don't use "subdir-objects" yet because it breaks "make distclean" when
 # dependencies are enabled (as of Automake 1.14.1) due to this bug:
-# http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17354
+# https://debbugs.gnu.org/cgi/bugreport.cgi?bug=17354
 # The -Wno-unsupported is used to silence warnings about missing
 # "subdir-objects".
 AM_INIT_AUTOMAKE([1.12 foreign tar-v7 filename-length-max=99 -Wno-unsupported])
diff --git a/dos/INSTALL.txt b/dos/INSTALL.txt
index 4c13211f..e5ba85bd 100644
--- a/dos/INSTALL.txt
+++ b/dos/INSTALL.txt
@@ -17,7 +17,7 @@ Introduction
 
 Getting and Installing DJGPP
 
-    You may use <http://www.delorie.com/djgpp/zip-picker.html> to help
+    You may use <https://www.delorie.com/djgpp/zip-picker.html> to help
     deciding what to download. If you are only interested in building
     XZ Utils, the zip-picker may list files that you don't strictly
     need. However, using the zip-picker can still be worth it to get a
@@ -25,7 +25,7 @@ Getting and Installing DJGPP
     from readme.1st too).
 
     For a more manual method, first select a mirror from
-    <http://www.delorie.com/djgpp/getting.html> and go the
+    <https://www.delorie.com/djgpp/getting.html> and go the
     subdirectory named "current". You need the following files:
 
         unzip32.exe  (if you don't already have a LFN-capable unzipper)
diff --git a/src/liblzma/api/lzma.h b/src/liblzma/api/lzma.h
index ba4abd8c..4d8e3994 100644
--- a/src/liblzma/api/lzma.h
+++ b/src/liblzma/api/lzma.h
@@ -8,16 +8,16 @@
  * format and raw (no headers) streams are supported. Multiple compression
  * algorithms (filters) are supported. Currently LZMA2 is the primary filter.
  *
- * liblzma is part of XZ Utils <http://tukaani.org/xz/>. XZ Utils includes
+ * liblzma is part of XZ Utils <https://tukaani.org/xz/>. XZ Utils includes
  * a gzip-like command line tool named xz and some other tools. XZ Utils
  * is developed and maintained by Lasse Collin.
  *
  * Major parts of liblzma are based on Igor Pavlov's public domain LZMA SDK
- * <http://7-zip.org/sdk.html>.
+ * <https://7-zip.org/sdk.html>.
  *
  * The SHA-256 implementation is based on the public domain code found from
- * 7-Zip <http://7-zip.org/>, which has a modified version of the public
- * domain SHA-256 code found from Crypto++ <http://www.cryptopp.com/>.
+ * 7-Zip <https://7-zip.org/>, which has a modified version of the public
+ * domain SHA-256 code found from Crypto++ <https://www.cryptopp.com/>.
  * The SHA-256 code in Crypto++ was written by Kevin Springle and Wei Dai.
  */
 
diff --git a/src/liblzma/check/sha256.c b/src/liblzma/check/sha256.c
index 5eede5ce..6feb3425 100644
--- a/src/liblzma/check/sha256.c
+++ b/src/liblzma/check/sha256.c
@@ -8,7 +8,7 @@
 ///             conditionally to keep the code working on older boxes.
 //
 //  This code is based on the code found from 7-Zip, which has a modified
-//  version of the SHA-256 found from Crypto++ <http://www.cryptopp.com/>.
+//  version of the SHA-256 found from Crypto++ <https://www.cryptopp.com/>.
 //  The code was modified a little to fit into liblzma.
 //
 //  Authors:    Kevin Springle
diff --git a/src/xz/xz.1 b/src/xz/xz.1
index caa5a068..aefb79f2 100644
--- a/src/xz/xz.1
+++ b/src/xz/xz.1
@@ -3017,4 +3017,4 @@ XZ Utils: <https://tukaani.org/xz/>
 .br
 XZ Embedded: <https://tukaani.org/xz/embedded.html>
 .br
-LZMA SDK: <http://7-zip.org/sdk.html>
+LZMA SDK: <https://7-zip.org/sdk.html>
diff --git a/windows/INSTALL-MinGW.txt b/windows/INSTALL-MinGW.txt
index 90921711..72e2718f 100644
--- a/windows/INSTALL-MinGW.txt
+++ b/windows/INSTALL-MinGW.txt
@@ -32,7 +32,7 @@ Installing the toolchain(s)
     So you need to pick between MinGW and MinGW-w32 when building
     32-bit version. You don't need both.
 
-    You might find 7-Zip <http://7-zip.org/> handy when extracting
+    You might find 7-Zip <https://7-zip.org/> handy when extracting
     some files. The ready-made build script build.bash will also use
     7-Zip to create the distributable .zip and .7z files.
 
@@ -50,7 +50,7 @@ Installing MSYS
 
     You can download MSYS from MinGW's Sourceforge page:
 
-        http://sourceforge.net/projects/mingw/files/MSYS/Base/msys-core/
+        https://sourceforge.net/projects/mingw/files/MSYS/Base/msys-core/
 
     I recommend using MSYS 1.0.11 (MSYS-1.0.11.exe or
     msysCORE-1.0.11-bin.tar.gz) because that package includes all the
@@ -69,7 +69,7 @@ Installing MinGW
 
     You can download the required packages from MinGW's Sourceforge page:
 
-        http://sourceforge.net/projects/mingw/files/
+        https://sourceforge.net/projects/mingw/files/
 
     These version numbers were the latest when I wrote this document, but
     you probably should pick the latest versions:
@@ -94,9 +94,9 @@ Installing MinGW-w32 or MinGW-w64
     toolchain. For XZ Utils 5.2.0 I used the packages from these
     directories:
 
-        http://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/4.9.2/threads-win32/sjlj/
+        https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/4.9.2/threads-win32/sjlj/
 
-        http://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/4.9.2/threads-win32/sjlj/
+        https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/4.9.2/threads-win32/sjlj/
 
     If you install both MinGW-w32 and MinGW-w64, remember to extract
     them into different directories. build.bash looks at