diff --git a/doc/manual/command-ref/conf-file.xml b/doc/manual/command-ref/conf-file.xml
index 3512777dd71dc35dd8df522ce9320819a7f95627..47ceff2625ea67da01914708720a29aaa7581747 100644
--- a/doc/manual/command-ref/conf-file.xml
+++ b/doc/manual/command-ref/conf-file.xml
@@ -262,7 +262,7 @@ false</literal>.</para>
     system (except that fixed-output derivations do not run in private
     network namespace to ensure they can access the network).</para>
 
-    <para>Currently, sandboxing only work on Linux and Mac OS X. The use
+    <para>Currently, sandboxing only work on Linux and macOS. The use
     of a sandbox requires that Nix is run as root (so you should use
     the <link linkend='conf-build-users-group'>“build users”
     feature</link> to perform the actual builds under different users
diff --git a/doc/manual/installation/installing-binary.xml b/doc/manual/installation/installing-binary.xml
index 2a9beec98c9bebba07baf42c748abfd0d7a4bda2..24e76eafeb1877999d2c2af5d5b1fdccf39b9787 100644
--- a/doc/manual/installation/installing-binary.xml
+++ b/doc/manual/installation/installing-binary.xml
@@ -6,7 +6,7 @@
 
 <title>Installing a Binary Distribution</title>
 
-<para>If you are using Linux or Mac OS X, the easiest way to install
+<para>If you are using Linux or macOS, the easiest way to install
 Nix is to run the following command:
 
 <screen>
@@ -39,7 +39,7 @@ behaviour.
 <!--
 <para>You can also manually download and install a binary package.
 Binary packages of the latest stable release are available for Fedora,
-Debian, Ubuntu, Mac OS X and various other systems from the <link
+Debian, Ubuntu, macOS and various other systems from the <link
 xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>.
 You can also get builds of the latest development release from our
 <link
diff --git a/doc/manual/installation/multi-user.xml b/doc/manual/installation/multi-user.xml
index 49c4f723597e3e1e444bd09d243649e88a85b6c5..a13e3c89be78181dc51c59ad6e6c3d490b0f2e95 100644
--- a/doc/manual/installation/multi-user.xml
+++ b/doc/manual/installation/multi-user.xml
@@ -52,7 +52,7 @@ This creates 10 build users. There can never be more concurrent builds
 than the number of build users, so you may want to increase this if
 you expect to do many builds at the same time.</para>
 
-<para>On Mac OS X, you can create the required group and users by
+<para>On macOS, you can create the required group and users by
 running the following script:
 
 <programlisting>
diff --git a/doc/manual/installation/supported-platforms.xml b/doc/manual/installation/supported-platforms.xml
index cbe528690cd9c5bf0ca53d3547b1c6b3acb42c8a..a468a56406370526cf943f0a09132337af80adf2 100644
--- a/doc/manual/installation/supported-platforms.xml
+++ b/doc/manual/installation/supported-platforms.xml
@@ -12,7 +12,7 @@
 
   <listitem><para>Linux (i686, x86_64).</para></listitem>
 
-  <listitem><para>Mac OS X (x86_64).</para></listitem>
+  <listitem><para>macOS (x86_64).</para></listitem>
 
   <!--
   <listitem><para>FreeBSD (only tested on Intel).</para></listitem>
diff --git a/doc/manual/introduction/about-nix.xml b/doc/manual/introduction/about-nix.xml
index be065da3eb2dd4a03ea8761105387754698401af..7cb124033f3e31001f8cdad4e8614ae42a14003e 100644
--- a/doc/manual/introduction/about-nix.xml
+++ b/doc/manual/introduction/about-nix.xml
@@ -236,7 +236,7 @@ href="[%root%]hydra">a continuous build system</a>.</para>
 
 <simplesect><title>Portability</title>
 
-<para>Nix runs on Linux and Mac OS X.</para>
+<para>Nix runs on Linux and macOS.</para>
 
 </simplesect>
 
diff --git a/src/libutil/archive.cc b/src/libutil/archive.cc
index e0e6f5dfd73c3e06335310ef242dab3ae174bfc6..ed48c1349d85bdaea33a4c2c9eb76cd3900d6311 100644
--- a/src/libutil/archive.cc
+++ b/src/libutil/archive.cc
@@ -72,7 +72,7 @@ static void dump(const Path & path, Sink & sink, PathFilter & filter)
     else if (S_ISDIR(st.st_mode)) {
         sink << "type" << "directory";
 
-        /* If we're on a case-insensitive system like Mac OS X, undo
+        /* If we're on a case-insensitive system like macOS, undo
            the case hack applied by restorePath(). */
         std::map<string, string> unhacked;
         for (auto & i : readDirectory(path))