diff --git a/README.md b/README.md
index 6829d9a08df3b..5bba01876b595 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 
 || **Status** |
 |---|---|
-|**OS X**         |[![Build Status](https://ci.swift.org/job/oss-swift-incremental-RA-osx/badge/icon)](https://ci.swift.org/job/oss-swift-incremental-RA-osx)|
+|**macOS**         |[![Build Status](https://ci.swift.org/job/oss-swift-incremental-RA-osx/badge/icon)](https://ci.swift.org/job/oss-swift-incremental-RA-osx)|
 |**Ubuntu 14.04** |[![Build Status](https://ci.swift.org/job/oss-swift-incremental-RA-linux-ubuntu-14_04/badge/icon)](https://ci.swift.org/job/oss-swift-incremental-RA-linux-ubuntu-14_04)|
 |**Ubuntu 15.10** |[![Build Status](https://ci.swift.org/job/oss-swift-incremental-RA-linux-ubuntu-15_10/badge/icon)](https://ci.swift.org/job/oss-swift-incremental-RA-linux-ubuntu-15_10)|
 
@@ -51,10 +51,10 @@ discussed below.
 
 ### System Requirements
 
-OS X, Ubuntu Linux LTS, and the latest Ubuntu Linux release are the current
+macOS, Ubuntu Linux LTS, and the latest Ubuntu Linux release are the current
 supported host development operating systems.
 
-For OS X, you need [the latest Xcode](https://developer.apple.com/xcode/downloads/).
+For macOS, you need [the latest Xcode](https://developer.apple.com/xcode/downloads/).
 
 For Ubuntu, you'll need the following development dependencies:
 
@@ -90,7 +90,7 @@ uploading SSH keys to GitHub):
 [CMake](http://cmake.org) is the core infrastructure used to configure builds of
 Swift and its companion projects; at least version 2.8.12.2 is required. Your
 favorite Linux distribution likely already has a CMake package you can install.
-On OS X, you can download the [CMake Binary Distribution](https://cmake.org/download),
+On macOS, you can download the [CMake Binary Distribution](https://cmake.org/download),
 bundled as an application, copy it to `/Applications`, and add the embedded
 command line tools to your `PATH`:
 
@@ -99,7 +99,7 @@ command line tools to your `PATH`:
 #### Ninja
 [Ninja](https://ninja-build.org) is the current recommended build system
 for building Swift and is the default configuration generated by CMake. If
-you're on OS X or don't install it as part of your Linux distribution, clone
+you're on macOS or don't install it as part of your Linux distribution, clone
 it next to the other projects and it will be bootstrapped automatically:
 
 ##### Build from source
@@ -115,7 +115,7 @@ it next to the other projects and it will be bootstrapped automatically:
     git checkout release
     cat README
 
-#### Install via third-party packaging tool (OS X only)
+#### Install via third-party packaging tool (macOS only)
 
 **[Homebrew](http://brew.sh/)**
 
@@ -151,7 +151,7 @@ Ninja:
     utils/build-script -x
 
 The Xcode IDE can be used to edit the Swift source code, but it is not currently
-fully supported as a build environment for SDKs other than OS X. If you need to
+fully supported as a build environment for SDKs other than macOS. If you need to
 work with other SDKs, you'll need to create a second build using Ninja.
 
 ## Testing Swift